Method for manufacturing printed wiring board

ABSTRACT

A composite layer composed of an Ni layer and a Pd layer is formed on a solder pad, and a solder on the composite layer is composed of a solder containing no lead. Because a Pd layer (palladium layer) reduces phenomenons such as repellency of the solder, adhesiveness with the solder can be enhanced. Because a Pd layer has a higher degree of rigidity than a gold layer, thermal stress is absorbed into the Pd layer and buffered so as to reduce the degree of transmission of stress to the solder bump, or to the solder layer, by thermal stress.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims the benefit of priorityunder 35 U.S.C. §120 from U.S. Ser. No. 11/576,987, filed Nov. 12, 2007,the entire contents of this application is incorporated herein byreference. U.S. Ser. No. 11/576,987 is a National Stage of PCTapplication No. PCT/JP05/04558, filed Mar. 15, 2005, and claims thebenefit of priority under 35 U.S.C. §119 from Japanese PatentApplication Nos. 2004-300696, filed Oct. 14, 2004; 2004-300697, filedOct. 14, 2004; 2004-373471, filed Dec. 24, 2004; and 2004-373472, filedDec. 24, 2004.

TECHNICAL FIELD

The present invention relates to a multilayered printed wiring board foraccommodation of a semiconductor, on which a semiconductor device isloaded.

BACKGROUND ART

The outermost layer of a printed wiring board generally has a solderresist layer in order to protect a conductor circuit. When a solder bumpis to be formed, a solder pad is formed by opening part of the solderresist such that the interior is exposed in order to connect to theconductor circuit. After a nickel layer and a gold layer have beenapplied onto a section that is to become a solder pad solder paste isprinted thereon and reflow operation is performed so as to form thesolder bump. The solder layer is formed at a portion that connects withan external board, and an externally connecting terminal is disposed. Asprior art, JP 10-154876 A has been proposed.

PRIOR ART 1

JP 10-154876 A is incorporated herein by reference.

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, if the diameter of the solder pad is small (for example, theopening diameter of the solder pad is less than 200 μm), when the solderpaste is formed on the solder pad by means of printing, the shape of thesolder bump, or of the solder layer that connects with the externalterminal sometimes cannot be maintained because of a defect such asinsufficient charging, or a lack of charging of the solder on the pad,and on occasions functioning as a solder bump, or as a solder layer,becomes impossible. Consequently, the degree of electric connectivityand reliability may on occasions drop.

Further, as the diameter of the opening of the solder pad decreases, theconnecting area between the solder pad and the solder bump may forexample, decrease and this may at times result in a deterioration inadhesive property.

Further, bubbles may be formed in the solder paste or in the solderlayer, and such bubbles may cause the solder to burst, or bubbles mayremain in the solder, and this may on occasions lead to a deteriorationin the ability of the solder perform a functions of electricconnectivity. This has resulted in a deterioration in the degree ofreliability at an early stage.

Further, there is a requirement for thermal stress to be buffered morethan in the case of a conventional solder pad structure (nickel-gold).In the first place, if thermal stress occurs, the thermal stress isapplied onto the solder bump or onto the solder layer. Concomitantlywith decreases in the opening diameter of the opening of the solder pad,defects such as the destruction or cracking or a solder bump, or of asolder layer are produced. As a result, the degree of electricconnectivity and the degree of reliability of the printed wiring boarddiminish.

For these reasons, the degree of strength and the level of corrosionresistance between the solder pad and the metal in the solder layer, orbetween one solder bump and another, need to be reinforced.

In particular, in reliability tests such as are performed under heatcycle condition, or in high temperature/and high humidity conditions, ithas proved difficult to maintain reliability as a printed wiring boardover the duration of a long period.

Further, if a solder containing no lead is used for the solder bump, itsdegree of toughness is lower than in the case of a solder containinglead and further because stress is not absorbed in the intenor, therehas been a tendency for the degree of imperfection to become morepronounced.

The present invention has been achieved to attain the issue describedabove, and an object of the invention is to provide, by adopting asolder pad structure that excels in terms of strength and adhesionproperty, a printed wiring board which secures excellent adhesiveproperty, electric connectivity and reliability and a manufacturingmethod of the same.

Means for Attaining the Issue First Invention: First Embodiment, SecondEmbodiment

As a result of assiduous research on the part of the inventor, in thepresent invention a printed wiring board has been achieved in whichsolder pads are formed by making an opening in a part of the solderresist layer, a composite layer is provided on the front surface of aconductor circuit that is exposed from the solder pad and a solder bump,or a solder layer, for connection to the exterior, is formed on thecomposite layer, characterized insofar that the composite layer iscomposed of an Ni layer (nickel layer) and a Pd layer (palladium layer).

Further, in the present invention a printed wiring board has beenachieved in which solder pads are formed by making an opening in a partof the solder resist layer, a composite layer is provided on the frontsurface of a conductor circuit that is exposed from the solder pad, anda solder bump, or a solder layer, for connection to the extend of, isformed on the composite layer, characterized insofar that the compositelayer is composed of an Ni layer and a Pd layer, and that the solderbump, or the solder layer, is composed of a solder containing no lead.

In the composite layer of the present invention, an Ni layer and a Pdlayer are overlaid successively from the side at which a conductorcircuit is located. In other words, a composite layer composed of an Nilayer and a Pd layer is overlaid on the conductor circuit from thesolder pad and then the solder bump, or the solder layer, is formedthereon. The solder bump is intended to be electrically connected with adevice such as a semiconductor device, while the solder layer isintended to be electrically connected with an external board throughexternal connecting terminals (BGA, PGA or the like).

A Pd layer (palladium layer) can reduce the chances of a defectoccurring such as the eventuality of a repellent solder. Thus, incomparison with a conventional solder pad structure, the degree ofadhesiveness with a solder can be further improved.

The reasons are that, in the case of palladium formed by plating,defects such for this as deposition failure are unlikely to occur, andthat in comparison with Au layer (gold layer) the case of the palladiumlayer the ratio of oxide film formed on the front surface is smaller.Thus, even when the solder is mounted, a defect such as a repellentsolder occurs less frequently. Further, a solder bump, or a solderlayer, of a desired size can be formed within the solder pad.Consequently, because a solder bump or a solder layer adhesion betweenthe solder bump, or the solder layer is formed in a desired size,adhesiveness between the solder bump, or the solder layer, and theconductor circuit tends not to deteriorate. Further, the standard offunctioning as a printed wiring board will also tend not to deteriorate.

Furthermore, use of the palladium layer facilitates buffering of thermalstress in consequence, the chances of defects occurring in the solderbump, or in the solder layer, can be reduced, and it thus becomespossible to enhance levels of electric connectivity and reliability.

The reasons for this are that in comparison with gold, a palladium layerhas a superior degree of rigidity. Thus, thermal stress can be absorbedwithin the Pd layer and buffered. Consequently, the frequency of withwhich stress is transmitted to the solder bump, or to the solder layer,by means of thermal stress can be reduced. In consequence, the solderbump or the solder layer is unlikely to be damaged. Thus, deficienciesin electric connection stemming from the solder bump, or from the solderlayer, are much less liable to occur, and reliability can be securedover long periods of time, even than reliability tests are performed.

By adopting a composite layer structure, in comparison with the case ofa conventional solder pad structure (nickel-gold layer), degree ofelectric connectivity and reliability can be enhanced.

Furthermore, the effects of doing so become more pronounced if a soldercontaining no lead (lead free) is used in the solder bump or in thesolder layer, a solder free of lead is inferior to a solder containinglead in terms of the buffering of thermal stress. In the first place, asolder containing lead (for example, Sn/Pd=6:4) buffers stress withinthe solder the concomitantly with degree of thermal stress induced. Thelead contained in the solder absorbs the stress. However, a solder thatis free of lead is inferior to a solder containing lead in term of thedegree of force in buffering stress. Thus, by providing a solder padwith a composite layer composed of an Ni layer and a Pd layer, stresscan be buffered by means of the entire solder pad structure.Consequently, adhesiveness of the solder itself is superior to that inthe case of a conventional solder pad structure (Ni layer-Au layer),stress relative to the thermal stress can be bufferedmore easily anddefects such as destruction and cracking in a solder bump, or in asolder layer that is formed can be inhibited. For these reasonsaccording to this invention higher levels of electric connectivity andreliability can be secured than in the case of a type in which a solderfree of lead is applied to the conventional solder pad structure.

Further, a composite layer composed of an Ni layer and a Pd layer isprovided on a conductor circuit on the solder pad, and a solder bump, ora solder layer, is formed on the composite layer, by means of reflow. Atthis time, either an Ni layer-NI alloy layer structure, an Ni layer-Snalloy layer structure, or a solder layer or solder bump structure isformed on the conductor circuit which serves as the solder pad. In thiscontext, an Ni alloy layer or an Ni—Sn alloy layer can enhanceadhesiveness on the solder layer. In other words, resistance to pullingcan be intensified so that the degree of rigidity of either the Ni alloylayer or the Ni—Sn alloy layer can be reinforced. As a result, thedegree of resistance to peeling can be improved.

An Ni alloy layer or an Ni—Sn alloy layer of this type can reinforce thedegree of resistance to pulling, irrespective of its size. In otherwords, an Ni alloy layer or an Ni alloy can inhibit reductions of thelevel of resistance to peeling.

In this context, the Ni alloy layer or the Ni—Si alloy layer can enhanceadhesiveness on the solder layer. In other words, because an Ni alloylayer or an Ni—Sn alloy layer intensifies the degree of rigidity,resistance to pulling can be intensified. In consequence, reductions inthe degree of resistance to peeling can be obviated.

An Ni alloy layer or an Ni—Sn alloy layer of this type can intensifyresistance to pulling, irrespective of its size. In other words, in thiscase, an Ni alloy layer or an Ni—Sn alloy layer can inhibit reductionsin the degree of the resistance to peeling irrespective of the size ofthe solder pad. An Ni alloy layer is an alloy layer containing Ni andSn, and elements such as Cu, Bi and In may also be included. As long asthe ratio occupied by Ni is high, a two-component base or a base made upof three or more components is possible.

An Ni—Sn alloy layer is an alloy layer which contains Ni and Sn, and mayalso contain Cu, Bi or In. As long as the ratio that is principallyoccupied by Ni and Sn is high the layers may be of a two-component baseor a base made up of three or more components. For example, the layermay be an alloy layer containing combinations such as Ni, Sn and Cu orNi, Sn and Bi.

An Ni alloy or an Ni—Sn alloy layer can inhibit reductions in the degreeof rigidity.

By adjusting a thickness of an Ni alloy layer or an Ni—Sn alloy layer,reductions in the degree of bonding strength between a nickel layer anda solder bump can be inhibited and reductions in the degree ofresistance to pulling can be inhibited.

An average thickness of an Ni alloy layer or the Ni—Sn alloy layer ispreferred to be 1.0-2.5 μm. The reason is that this range deceleratesreduction of rigidity of the Ni alloy layer or Ni—Sn alloy layer more sothat reduction of the resistance to pulling can be decelerated.

Here, the average thickness is set to less than 1.0 μm. However, if theaverage thickness exceeds 2.5 μm, the rigidity of the Ni alloy layer, orof the Ni—Sn alloy layer, can still be secured and either of such layerscan be used under ordinary conditions. However, the degree of rigidityin such conditions is inferior to a case where thickness of the Ni—Snalloy layer is within the range mentioned above, and resistance topulling on occasions may also be inferior.

As a result of experiments, it has been discovered that, the averagethickness of an Ni alloy layer, or of an Ni—Sn alloy layer, can bewithin a range of between 1.0 and 2.5 μm by adjusting the degree ofthickness of the Ni layer and the amount of P content therein, or thedegree of thickness of the Pd layer and the amount of P content therein.In other words, if when the solder bump is formed, the composite layeris made up of an Ni layer and a Pd layer, or of an Ni layer, a Pd layerand a precious metal layer, the Pd layer, or the Pd layer and theprecious metal layer, is diffused and an Ni alloy layer, or an Ni—Snalloy layer, is formed. At this time, the thickness of the Ni alloylayer, or of the Ni—Sn alloy layer, can be adjusted by means of thethickness of the Ni layer. Combined with the amount of the P content, orby means of the thickness of the Pd layer combined with the amount ofthe P content. Thus, by adjusting the thickness of the Pd layer, thethickness of the Ni—Sn alloy layer can be modified and consequently, thedegree of rigidity of the Ni—Sn alloy layer becomes less likely todecrease, and the resistance to pulling also becomes less likely todiminish.

The Ni alloy layer or the Ni—Sn alloy layer is constituted of particleshaving any shape selected from among a sheet-like body, a column-likebody and a grain-like body. Such a layer may be constituted of a singlebody selected from among them (for example, lamination in which onlysheet-like bodies are piled on top of one another), or it may be ofcompound structure thereof (for example, lamination in which asheet-like body and a column-like body are combined). An alloy layerconstituted of mainly sheet-like bodies is preferable. In the case ofsheet-like bodies, it becomes difficult for gaps to be formed betweenone sheet-like body and another, and they can be piled up easily. Thus,an alloy layer constituted of mainly sheet-like bodies can secure adegree of rigidity easily. It can also secure easily resistance topulling relative to the solder. It is particularly preferable that sucha layer be an alloy layer constituted of only sheet-like bodies.

Further, an Ni—Sn alloy layer (for example, Ni, Sn and Cu) is preferablyan alloy layer constituted of a three-component base. An alloy layerconstituted of a three-component base enables components to be mixedevenly and for the configuration of the layer to be uniform. For thisreason, it makes separation unlikely within the alloy layer and rigiditycan be easily secured. Further, an alloy layer of this kind enables theshapes of its particles to turn easily into sheet-like bodies and alsofacilitates an increase in the degree of rigidity.

Further, if an alloy layer constituted of a three-component base is in arange of Sn:Cu:Ni=30-90:10-50:1-30, its degree of rigidity tends todiminish easily. In particular, if a solder containing no lead (free oflead) is used for the solder bump, or for the solder layer, it becomespossible for stress caused by thermal stress to be easily buffered.Thus, damage or cracking is unlikely to be induced within a solder freeof lead, and degrees of electric connectivity and reliability can beenhanced. In particular, in an Ni—Cu—Sn alloy layer whose Sn is 40-50 wt%, the degree of rigidity can be easily raised.

If the thickness of an Ni layer is 0.05-10.0 μm, the average thicknessof an Ni alloy layer, or of an Ni—Sn alloy layer, can be easily changedto 1.0-2.5 μm.

Thus, if the thickness of an Ni layer is less than 0.05 μm, thethickness of the Ni alloy layer can be easily reduced because Nidiffusion is not achieved to a sufficient degree. As a result, thethickness of an Ni alloy layer can be made less than 1.0 μm, anddepending on the circumstances, an Ni alloy layer may be, lost ordamaged, and consequently, the degree of rigidity of the solder pad mayon occasions diminish.

If, in contrast, the thickness of an Ni layer exceeds 10.0 μm, Nidiffusion is performed sufficiently so that formation of the Ni alloylayer is boosted, the amount of Ni content in the Ni alloy increases(for example, the amount of Ni content in a three-component base alloyof Sn—Ni—Cu increases), and it accordingly becomes easy to increase thethickness of the Ni alloy layer. In such circumstances, the averagethickness of an Ni alloy layer, or of an Ni—Sn alloy layer, tends toexceed 2.5 μm, thereby, on occasions, reducing the degree rigidity ofthe Ni alloy layer or the Ni—Sn alloy layer.

Further, the Ni layer is preferable between 0.05 and 1.0 μm. Within sucha range, the thickness of the Ni alloy layer, or of the Ni—Sn alloylayer, never moves outside the of 1.0 to 2.5 μm range, and the Ni alloylayer, or the Ni—Sn alloy layer, maintains continuity and is unlikely tobe lost or damaged. In other words, the degree of rigidity of a solderpad becomes unlikely to decrease.

Further, the Ni layer is most preferably between 0.05 and 0.3 μm. Withinthis range, an Ni alloy layer or an Ni—Sn alloy layer can be formedregardless of which composition is used for the soldering. In otherwords, because the amount of Ni content in an Ni alloy layer, or in anNi—Sn alloy layer tends not to increase, an Ni alloy layer or an Ni—Snalloy layer can be confined to within a desired range, and the degree ofrigidity in the solder pad tends to drop.

If the thickness of a Pd layer is set to between 0.01 and 1.0 μm, theaverage thickness of an Ni—Sn alloy layer can be easily adjusted to1.0-2.5 μm.

In this context, a Pd layer performs a role of inhibiting Ni diffusionso as to inhibit formation of an Ni alloy layer or an Ni—Sn alloy layer.Thus, if the thickness of a Pd layer is less than 0.01 μm, Ni diffusioncannot be suppressed and consequently, the thickness of the Ni alloylayer, or of the Ni—Sn alloy layer may be easily increased. In thesecircumstances, the average thickness of an Ni alloy layer tends toexceed 2.5 μm and thus, it becomes difficult to enhance the rigidity ofan Ni alloy layer or of an Ni—Sn alloy layer.

In contrast, if the thickness of a Pd layer exceeds 1.0 μm, Ni diffusionis inhibited and the formation of an Ni alloy layer, or of an Ni—Snalloy layer, can be hampered. Consequently, the thickness of an Ni alloylayer, or an Ni—Sn alloy layer can be reduced easily. In thesecircumstances, the average thickness of an Ni alloy layer or of an Ni—Snalloy layer, tends to be less than 0.01 μm, and it becomes difficult toenhance the degree of rigidity of the Ni alloy layer, or of the Ni—Snalloy layer.

In particular, the thickness of the Pd layer is preferably between 0.03and 0.2 μm. The reason for this is that within this range, the thicknessof a Pd layer enters a range of between 0.01 and 1.0 μm even whenthickness has been dispersed locally. Thus, an Ni alloy layer, or anNi—Sn alloy layer can be easily formed within the desired range andconsequently the degree of rigidity of an Ni alloy layer, or of Ni—Snalloy layer, tends not to decrease.

The thickness of an Ni alloy layer can be controlled, and the degree ofrigidity of the Pd layer can be reinforced by the amount of content ofphosphor (P) in the Pd layer.

The amount of P content in the Pd layer is preferably 2-7 wt %.Consequently, a Pd layer that is formed is unlikely to be porous, a filmthickness is likely to be uniform, and formation of an oxide film on thefront layer can be inhibited. Further, it becomes easy to secure therigidity of the Pd layer formed.

Furthermore, because it becomes easy to form an Ni alloy layer, or anNi—Sn alloy layer, rigidity of the Ni alloy layer, or of the Ni—Sn alloylayer can be easily secured.

In this context, if the amount of content of P in the Pd layer is lessthan 2%, or if the amount of the content of P in the Pd layer exceeds7%, the Pd layer cannot be applied to the Ni layer uniformly, and poresremain in the Pd layer. Oxide film can be easily formed on the frontsurface of the Pd layer, so that even if a solder is formed, the degreeof adhesiveness tends to decrease. Further, the degree of rigidity ofthe Pd layer may sometimes diminish thereby making buffering of thermalstress. Thus, stress may on occasions concentrate on the solder bump, oron the solder layer sometimes lending to defects such as damage orcracking in the solder. Long-term reliability tends to become difficultto secure when reliability tests are performed. In normal conditions,however reliability can still be secured.

An Ni alloy layer, or the Ni—Sn alloy layer, that is formed after thereflowing of solder tends to be formed thick. As a result, the of an Nialloy layer, or an Ni—Sn alloy layer formed cannot easily be enhanced,even though the layer can perform its function. As an extreme example,the average thickness of an Ni alloy layer, or an Ni—Sn alloy layer, mayon occasions exceed 2.5 μm.

Further, the amount of the content of P in the Pd layer is particularlypreferably 4-6 wt %. If the amount of the content of P is set withinthis range, the amount of content of P never fluctuates widely beyond2-7 wt % even when local deflection occurs. It becomes difficult foroxide film to be formed on the front surface of the Pd layer that isformed and when the solder is formed the drawback of repellency on thepart of the solder rarely occurs, and adhesiveness is thereby secured.Further, the rigidity of the Pd layer itself is secured and buffering ofstress to thermal stress is facilitated. In consequence, defects such asdamage or cracking become unlikely to be induced in a solder formed onthe Pd layer and degree of electric connectivity and reliability arenever reduced. Even when a heat reliability test is performed under heatcycle conditions or in conditions at high temperature and high humidity,a deterioration in functioning occurs slowly, and reliability can beeasily secured over a long period.

Further, the thickness of the Ni alloy layer, or of the Ni—Sn alloylayer formed by reflowing solder can be contained within a predeterminedrange. As a result, the degree of rigidity of the Ni alloy layer or ofthe Ni—Sn alloy layer can be easily enhanced. In other words, the degreeof rigidity of such a layer tends not to drop. The thickness of a Pdlayer, and the amount of the content of phosphor in the Pd film can beadjusted by adjusting conditions such as those relating to plating time,plating temperature, the composition of the plating solution, and the pHin the plating solution. Although thickness can vary, depending on thesize of a bath of the plating solution and the flow of the solution, itis preferable to seak a correlation with the thickness on the basis ofinitial conditions.

The reason why a Pd film having no pores is formed when an appropriateamount of P is added to the Pd layer will now be described withreference to FIG. 30.

FIG. 30(A) illustrates a case where an appropriate amount of P iscontained. In this context, formation of the Pd film is carried out byelectroless plating, and for the plating solution, a hypophosphorousacid base chemical liquid is used as its reducing agent. As one examplethereof, sodium hypophoshite (NaH2PO2) can be used. First, hypophoshiteions (H2PO2-) 63 are attracted onto the nickel layer ((1) in FIG.30(A)). Next, Ni serves as catalyst to make hypophoshite ions inducedehydrogenolysis (H2PO2−+2H−Pd+2H+). Hydrogen atoms 65 generated bymeans of this dehydrogenolysis are attracted onto the Ni surface andactivated ((2) in FIG. 30(A)). Pd ions (Pd2+) in the plating solutionreceives electrons from hydrogen on the Ni surface and are reduced(Pd2++2H−Pd+2H+) by Pd metal ((3) in FIG. 30(A)). With deposited Pdmetal acting as a catalyst, Pd is deposited on the Ni surface by meansof the same mechanism ((4) in FIG. 30(A)). In this context P in the Pd—Pis formed by a codeposit of hypophosphorous acid which acts as areducing agent. Because hypophosphorous acid plays a role in activatingNi as a catalyst, it can be plated on the Ni surface withoutselectivity, or, in other words, form a compact Pd layer. Further, byadjusting degree of concentration of the hypophosphorous acid, theamount of the content of Pin a film of the Pd layer can be adjusted.

FIG. 30(B) illustrates a case of pure Pd containing no P. Here,formation of the Pd film is carried out by electroless plating and, asits plating solution, a formic acid (HCOOH) containing no P is used as areducing agent. First, hydrogen atoms 65 generated during an Ni platingreaction are attracted onto the Ni surface ((1) in FIG. 30(B)). Next,when Pd ions in the plating solution make contact with hydrogen on theNi surface, the Pd ions are reduced to metal ((2) in FIG. 30(B)). Theformic acid is dissolved to H2 and CO2 by the influence of the Pddeposition reaction ((3) in FIG. 30(B)). The Pd ions receive electronsfrom hydrogen generated by decomposition of the formic acid and arereduced to metal ((4) in FIG. 30(B)). However, because a formic acidcannot act as a reducing agent during an early deposition period,hydrogen on the Ni surface serves as a reducing agent. However, becausemuch hydrogen does not exist on the Ni front surface, a plating filmhaving selectivity can be formed. In other words, a Pd plating layerhaving a porous configuration can be formed.

A determination of the quantity of each metal mentioned above is carriedout according to an energy dispersion method (EDS). According to thismethod, on electron beam, which is a source of excitation in a SEM (ascanning electron microscope) or in a TEM (a transmission electronmicroscope), is irradiated onto the surface of a specimen so as togenerate a variety of signals. In the course of this process, a mainlycharacteristic X ray is detected with a Si (Li) semiconductor detectorand electron-positive pairs of holes of a quantity proportional to itsenergy are produced in the semiconductor so as to generate electricsignals. After the electric signals have been amplified andanalogously/digitally converted, an X-ray spectrum is obtained byidentifying with a multi-channel analyzer, and identification ofelements is carried out from its peak energy by a quantitative analysisof that peak value. An energy dispersion type X-ray analyzer(manufactured by JEOL Ltd., JED-2140) was used for the measurement andquantitative analysis. By irradiating directly a metal layer that hasbeen formed, a quantitative measurement of the metal was executed.

The thickness of the Pd layer is preferably formed within a range ofbetween 0.01 and 1.0 μm. It is particularly preferable to form it withina range of between 0.03 and 0.7 μm. If the thickness of the Pd layer isless than 0.01 μm, the formation of the Ni alloy layer, or of the Ni—Snalloy layer can not be promoted. Consequently, Ni alloy layer or Ni—Snalloy layer is not formed locally and as a result, it becomes difficultto enhance the degree of rigidity of the Ni alloy layer, or of the Ni—Snalloy layer, and it becomes difficult to improve the resistance topeeling of the Ni—Sn alloy layer. If, in contrast, the thickness of thePd layer exceeds 1 μm, formation of the Ni alloy layer, or of the Ni—Snalloy layer may sometimes be hindered by that thickness. For thisreason, occasions may arise where no Ni alloy layer, or Ni—Sn alloylayer is formed locally, and the degree of rigidity of the Ni alloylayer, or of the Ni—Sn alloy layer, may sometimes deteriorate. As aresult, it becomes difficult to improve the resistance to peeling of theNi alloy layer, or of the Ni—Sn alloy layer (a predetermined degree ofresistance to peeling is, however secured).

The Ni layer constituting the composite layer in the present inventionis preferably formed with an alloy metal containing elements such asNi—Cu, Ni—P or Ni—Cu—P.

If an Ni layer is formed by forming film with pure Ni, the plating filmmay on occasions not be formed in all directions, and in consequencefine pores (defects) may be formed. An alloy metal forms a uniform filmbecause pores (defects) are buried. An Ni layer (intermediate) and a Pdlayer, and an Ni layer (intermediate), a Pd layer and a corrosionresistant layer, may be formed by either a physical method or by achemical method, or by using a combination of these methods, and theymay be formed in a either single layer, or in two or more layers.

In particular, it is preferably formed of an alloy metal of Ni—P, or ofNi—Cu—P. In other words, the Ni layer preferably contains P(phosphor). Afurther reason for this is that even if unevenness is formed on thesurface of the conductor circuit, a film whose front layer is flattenedcan be formed by killing that unevenness. Further, if the Ni layer isformed by plating, instances of a metal layer not being formed, orerrors in formation caused by non-deposition or a cessation of reaction,tend not to occur in the Ni layer formed. Further, formation of a Pdlayer that is formed on the Ni layer can be promoted and instances of alayer not being formed, or errors in the formation of the Pd layer tendto occur rarely. For this reason, a Pd layer that is desired can beformed and rigidity as a composite layer can be secured.

The amount of the content of P (phosphor) in the Ni layer isparticularly preferably between 0.5 and 15 wt %. If the amount of thecontent of P is less than 15%, or exceeds 15.0 wt %, formation of the Nilayer can easily be inhibited. Further, the formation of a Pd layer onthe Ni layer becomes more difficult to promote, and in consequent,defects such as instances of the non-formation of the Pd layer, anderrors in formation may be induced, and rigidity of the Pd layer issometimes not able to be secured. As a consequence it sometimes becomesdifficult to secure electric connectivity or reliability. Although noproblem arises in use as a printed wiring board for ordinary purposes,advantages can on occasions be secured in cases of printed wiring boardsfor which long-term reliability is sought.

The thickness of the nickel film and the amount of the content ofphosphor in the nickel film can be adjusted by factors such as adjustingthe plating time, the plating temperature, the composition of theplating solution and the PH of the plating solution. Although variationsmay occur, depending on the size of the bath for the plating solutionand the flow of the plating solution, it is preferable to seek acorrelation with the thickness on the basis of initial conditions.

P (phosphor) is preferably contained in both the Ni layer and the Pdlayer. If phosphor is contained in both, the Ni alloy layer or the Ni—Snalloy layer, becomes easy to form, and as a consequence, rigidity of thesolder bump in the solder pad, or in the alloy layer, formed in thesolder layer becomes less liable to deteriorate.

The amount of the content of P (phosphor) in the Ni layer is preferablylower than the amount of the content of P (phosphor) in the Pd layer. Inconsequence, the Ni layer tends to become covered by the Pd layer andseparation becomes unlikely to occur in an interface between the Pdlayer and the Ni layer. As a result, reductions in the degrees ofelectric connectivity or reliability caused by defects in the interfaceof the solder pad becomes unlikely to occur.

The amount of the content of P (phosphor) in the Ni layer is preferablyhigher than the amount of the content of P (phosphor) in the Pd layer.Consequently, when an alloy layer is formed by heat treatment of a Pdlayer and an Ni layer with a solder, it tends to turn into a sheet-likebody and consequently, it becomes easy to secure a desired, or higherdegree of rigidity in the solder pad.

As the solder for use in the present invention, it is permissible to usea solder with a two-component base, a solder with a three-component baseor a solder with a base of four or more components. As metals containedin these compositions, elements such as Sn, Ag, Cu, Pb, Sb, Bi, Zn, andIn may be used.

A two-component base solder may be of combinations such as Sn/Pb, Sn/Sb,Sn/Ag, Sn/Cu and Sn/Zn. A three-component base solder may be ofcombinations such as Sn/Ag/Cu, Sn/Ag/Sb, Sn/Cu/Pb, Sn/Sb/Cu, Sn/Ag/In,Sn/Sb/In, Sn/Ag/Bi and Sn/Sb/Bi. With regard to such three-componentbase solders, the three components may occupy more than 10 wt %, or themain two components may account for more than 95 wt % while theremainder may be accounted for by one component (for example, athree-component base solder in which a total of the Sn and At accountsfor 97.5 wt % while the remainder is accounted for by Cu).

A solder containing no lead (free of lead) may include combinations suchas a Sn/Ag base solder, a Sn/Bi base solder, a Sn/Zn base solder and aSn/Cu base solder. Such solders are inferior to Sn/Pb in terms ofbuffering of stress within the solder in relation to thermal stress.Thus, stress is likely to remain in the solder.

Additionally, a multi-component base solder may be used. Amulti-component base solder may include combinations such as Sn/Ag/Cu/Sband Sn/Ag/Cu/Bi. It is permissible to use a solder whose a dose has beenadjusted.

It is permissible to use a solder in which the Ni alloy layer, or theNi—Sn alloy layer, can be formed in an interface between a component ofthe solder and the Ni layer. The degree of rigidity can be reinforced bythis Ni alloy layer, or by an Ni—Sn alloy layer, thereby inhibiting areduction in the resistance of the solder to peeling.

Among such options it is preferable to use an Ni—Sn alloy layer that iscomposed of Ni—Sn—Cu. The degree of rigidity can be reinforced by thisalloy. Further, such an alloy may contain elements such as Ag, Sb, Bi,and Zn in addition to the three components of Ni, Sn, and Cu. Even ifsuch elements are contained, rigidity of the Ni—Sn—Cu alloy layer neverdeteriorates. However, if the total amount of such elements exceeds anyone of the metals of Sn, Ni, Cu, rigidity may deteriorate.

Further, the melting point of these solders is preferably between 150and 350° C. Even if the melting point of the solder is less than 150° oreven if, in contrast, the melting point of the solder is over 350° C.Formation of the Ni—Sn alloy layer may on occasions be hindered. Thereason for this is that even if the temperature is low, the formation ofan Ni—Sn alloy is difficult to achieve and if the temperature is high,the Ni is separated and it becomes difficult for the Ni—Sn alloy to beformed. For these reasons, an Ni—Sn alloy can be better formed at atemperature mentioned above.

In the printed wiring board of the present invention, a rough layer maybe formed in a conductor circuit on the front surface of the printedwiring board provided with the conductor circuit. The average roughness(Ra) is preferably 0.02-7μ. The rough layer enhances adhesivenessbetween the conductor circuit and the solder resist layer. Inparticular, the average roughness of a desired range is 1-5 μm. Withinthat range, a desired degree of adhesiveness can be obtained,irrespective of factors such as the composition and the thickness of thesolder resist layer.

As a method of forming the rough layer, a method of forming an alloylayer of Cu—Ni—P by electroless plating, a method of formation byetching with a cupric complex and an organic acid salt, and a method offormation by oxidation reduction are available. The rough layer may becovered with an element such as Sn or Zn, depending on thecircumstances.

The conductor circuit on the outermost layer is covered and protected bythe solder resist layer. A variety of resins may be used for the solderresist layer, and, for example, a thermosetting resin, a thermoplasticresin, a light curing resin, a thermoplastic resin partially transformedto (meta) acrylic, or a resin composite containing two or more of suchtypes may be used. The resin used may be a resin such as an epoxy resin,a phenol resin, a polyimide resin, a phenoxy resin or an olefin resin.

Formation of the solder resist layer is achieved by setting a level ofthe viscosity in advance and by coating with a resultant varnish-likeagent. Alternatively, a film-like agent in a semi-hardened condition (Bstage) can be affixed, and it is also permissible to use a method ofaffixing a film after coating. The film may be formed of plural layers,by means of using two or more resins.

Further, the solder resist layer can be provided with a solder pad byopening part of the layers. As a method of opening at this time, amethod can be used by placing on the solder resist layers a mask, onwhich an opening pad has been drawn, and by forming the solder pad byexposure and development (photo resist method), alternatively, a methodcan be adopted of opening part of the layer with a laser such as acarbon dioxide gas laser, an excimer laser or a YAG laser. Further, itis acceptable to use a method of making an opening for the solder padaccording to a direct drawing method.

In the case of a solder resist layer which is formed by exposure anddevelopment, a resin may be used that is obtained by means of hardening,for example, by using a bisphenol A type epoxy resin, a biphenol A typeepoxy resin acrylate, a novolac type epoxy resin or a novolac type epoxyresin acrylate with an amine base hardener or an imidazole hardener.

In particular, if the solder bump is formed by providing the solderresist layer with an opening, it is preferable that the solder resist becomposed of a “novolac type expoxy resin or a novolac type epoxy resinacrylate” and contain an “imidazole hardener” as its hardener.

Next, the solder resist layer is formed on the conductor circuit. Thethickness of the solder resist layer of the present invention should be5-40 μ. If it is too thin, it does not function as a solder dam, and ifit is too thick, it is difficult to bore and, moreover it will makecontact with the solder body and thereby cause cracking.

A solder resist layer of such a structure has an advantage insofar thatthere is a low degree of migration of lead (a phenomenon whereby leadions are diffused in the solder resist layer). Additionally, this solderresist layer is a resin layer that has been obtained by hardening theacrylate of the novolac type epoxy resin with an imidazole hardener,that has a superior degree of heat resistance and alkali resistance, andthat never deteriorates at temperatures (around 200° C.) at which asolder melts. Further, the solder resist layer can not be dissolved by astrong basic plating solution such as nickel plating, palladium platingor gold plating.

However, a solder resist layer of this type is likely to separatebecause it is composed of a resin that has a strict skeleton. A roughlayer is effective for purposes of preventing such separation.

As the acrylate of the aforementioned novolac type epoxy resin, it ispermissible to use an epoxy resin that has been obtained by reactingglycin ether of phenol novolac or cresol novolac with acrylic acid ormethacryl.

The aforementioned imidazole hardener should preferably be in liquidform at 25° C. The reason for this is that, if it is in liquid form, itcan be mixed uniformly.

As such a liquid imidazole hardener, 1-benzil-2-methyl imidazole(product name: 1B2MZ), 1-cyano ethyl-2-ethyl-4-methyl imidazole (productname: 2E4MZ-CN), 4-methyl-2-ethyl imidazole (product name: 2E4MZ) may beused.

The amount of imidazole hardener added is preferably 1-10 w % relativeto the total solid content of the solder resist compound. The reason forthis is that if the amount of hardener added is within this range, itcan be mixed uniformly.

As for the compound used before the hardening of the solder resist, itis preferable to use a glycol ether base solvent as its solvent.

A solder resist layer for which such compound is used never generatesfree oxygen, and never oxidizes the surface of the copper pad.Additionally, harm caused to the human body is minimal.

As such a glycol ether base solvent, at least one selected fromdiethylene glycol dimethyl ether (DMDG) and triethylene glycol dimethylether (DMTG) is preferably used. The reason for this is that by heatingat between 30 and 50° C. these solvents can completely dissolvebenzophenone or Michler's ketone which serve as initiating reagent.CH3O—(CH2CH2O)n-CH3 (n=1-5)This glycol ether base solvent should be 10-40 wt % relative to thetotal weight of the solder resist compound.

Furthermore, to the solder resist compounds described above can be addedvarious kinds of antifoam agents and leveling agents, a thermoplasticresin for purposes of enhancing heat resistance and resistance to bases,and for purposes of providing of plasticity, and, for purposes ofenhancing resolution, a photosensitive monomer.

For example, as the leveling agent, a leveling agent composed of apolymer of acrylic acid ester is preferably used. As the initiatingagent, IRUGACURE I907 manufactured by Ciba-Geigy is recommended, and asthe photosensitizing agent, DETX-S manufactured by NIPPON KAYAKU CO.,LTD.

Further it is permissible to add a pigment or colorant to the solderresist compound. This is because such an addition can hide the wiringpattern. As such a pigment, it is preferable to use a phthalocyaninegreen.

As the thermosetting resin added as a component, as mentioned above, abiphenol type epoxy resin may be used. Such bisphenol type epoxy resinsinclude a biphenol type A type epoxy resin and a biphenol F type epoxyresin and if resistance to bases is regarded as important, the former ispreferred. If the path of low viscosity is desirable (if a coatingproperty is to be given priority), the latter is preferable.

As the photosensitive monomer added as a component, as mentioned above,use of a multivalent acrylic base monomer can serve to improveresolution. For example, a multivalent acrylic base monomer manufacturedby NIPPON KAYAKU CO, LTD., DPE-6A or KYOEISHA CHEMICAL CO., LTD., R-604is preferable.

Preferably, these solder resist compositions are 0.5-10 Pa·s at 25° C.,and more preferably, 1-10 Pa·s, because a degree of viscosity is securedthat allows it to be applied easily with a roll coater. After the solderresist has been formed, an opening is formed. That opening is formed byexposure and development processing. It is acceptable to use acommercially marketed solder resist.

After the solder resist layer has been formed, a composite layer made upof the Ni layer and Pd layer is formed in the portion of the solderresist layer surrounding opening.

As an example, a metal layer containing Ni is formed by electrolessplating on a conductor circuit exposed from the solder pad. As examplesof a composition of plating solution, nickel sulfate 4.5 g/l, sodiumhypophosphite 25 g/l, sodium citrate 40 g/l, boracic acid 12 g/lthiouric acid 0.1 g/l (PH=11) are available. The portion of the solderresist layer surrounding the opening and the surface are washed with adegreasing solution, and a catalyst such as palladium is applied to aconductor portion exposed in the portion surrounding the opening so asto activate it. By means of dipping in the plating solution, a nickelplating layer is then formed.

After the nickel layer has been formed, the Pd layer is formed on the Nilayer.

As and when necessary, a corrosion resistant layer can be formed on thePd layer of a metal selected from Au, Ag, Pt and Sn. It is particularlypreferable for it to be formed of gold. Depending on the circumstances,two layers may be formed by means of displacement plating with the samemetal, and by means of electroless plating. The thickness is preferably0.01-2μ.

After the solder pad has been formed by producing a corrosion resistantlayer on the portion surrounding the opening, a solder paste of a solderthat is constituted by a two-component base solder, a three-componentbase solder or a multi-component base solder is applied onto the portionsurrounding the opening by means of printing. After that, it is passedthrough a nitrogen reflow at 250-350° C. and fixed to a solder pad thatis located in the portion surrounding the opening as a solder bump andthat to be connected to the semiconductor device. A solder containing nolead (free of lead) may be used.

Further, a solder layer is formed on the solder pad at an externalconnecting terminal, and the external connecting terminal (BGA, PGA orthe like) is mounted on the solder layer. Further, a component such as acapacitor may be loaded onto the solder layer.

Second Embodiment: Third Embodiment, Fourth Embodiment

As a result of researches by the inventor, a solder pad can be formedwith a part of the solder resist layer opened and a composite layerprovided on the conductor circuit that has been exposed from the solderpad.

One of the layers making up the composite layer of the present inventionis an Ni layer or Ni alloy layer (depending on circumstances, the Ni—Snalloy layer described above), and the other may be an Ni layer, anintermediate layer or a precious metal layer. These composite layers aredisposed on the solder pad and the solder bump and the solder layer areprovided so as to achieve an electric connection with the externalconnecting terminal (BGA, PGA or the like) which connects thesemiconductor device or an external board.

Example that can be considered for purposes of forming the Ni layer orthe Ni alloy layer as the composite layer, are an Ni layer, an alloylayer formed of Ni and another metal, an Ni—Sn alloy layer containingthe Ni layer and Ni—Sn, and an alloy layer containing the Ni layer andCu—Ni—Sn. Additionally, elements such as In, Bi and P may be contained.

Composite layers of this kind are provided on the conductor circuit onthe solder pad and a solder bump is formed on the composite layer byheating treatment such as a reflow. In cases of a solder layer, otherelectronic components, or external connecting terminals, can bedisposed. Consequently, a composite layer (an Ni layer and an Ni alloylayer or an Ni—Sn alloy layer), together with a solder layer or a solderbump are formed on the solder pad. In this context, the Ni alloy layer(or the Ni—Sn alloy layer) can enhance the level of adhesiveness withthe solder. In other words, because the Ni alloy reinforces the degreeof rigidity, the degree of resistance to pulling can be boosted. As aresult, in comparison with a conventional solder pad structure,resistance to peeling can be enhanced.

An Ni alloy layer of this kind can boost the degree of resistance topulling, irrespective of the size of the layer. In such circumstances,in comparison with a conventional solder pad structure an Ni alloy layercan enhance the degree of resistance to peeling irrespective of the sizeof the solder pad.

When an Ni layer, an intermediate layer or a precious metal layer areformed as a composite layer examples may include, a nickel layer (an Nilayer), a palladium layer (a Pd layer), a gold layer (an Au layer), anda nickel layer (an Ni layer) and a palladium layer (a Pd layer), and asilver layer (an Ag layer).

If any of such composite layers is provided and a solder layer or solderbumps are provided on the composite layer by reflow, the intermediatelayer and the precious metal layer are diffused toward the solder. Thus,an Ni alloy layer composed of Ni and a solder composition metal isformed on an interface between the nickel layer and the solder bump (anNi alloy layer may include a two-component or three-more component alloylayer composed of Ni and other metals, an Ni—Sn alloy layer containingNi—Sn and an alloy layer containing Cu—Ni—Sn).

In this context, an Ni alloy layer can enhance the degree ofadhesiveness with the solder layer or the solder bump. In other words,because the formation of an Ni alloy layer reinforces the level ofrigidity as a solder pad, the level of resistance to pulling can beboosted. As a result, in comparison with a conventional solder pad,reductions in the degree of resistance to peeling can be inhibited.

Irrespective of its size, an Ni alloy layer of this kind inhibitsreductions in the level of resistance to pulling. In other words, incomparison with the conventional solder pad structure, an Ni alloy layerinhibits reductions in resistance to peeling irrespective of the size ofthe solder pad, thus contributing to a rise in the level of resistanceto peeling.

An Ni alloy layer may, for example, include a two-component or a threeor more component alloy layer composed of Ni and another metal, an alloylayer containing Ni—Sn, an alloy layer containing Cu—Ni—Sn and the like.Ni alloy layers of this kind reinforce the level of rigidity of thesolder layer, or of the solder bump, in the solder pad.

By adjusting the degree of thickness of the Ni alloy layer, incomparison with a conventional solder pad structure, the bondingstrength of a solder pad portion composed of a nickel layer, an alloylayer (an Ni alloy layer or an Ni—Sn alloy layer) and a solder layer ora solder bump can be intensified, thereby leading to a rise in the levelof resistance to pulling.

The average thickness of an Ni alloy layer or an Ni—Sn alloy layer ispreferably between 1.0 and 2.5 μm. Within this range, it becomesdifficult for the degree of rigidity of the Ni alloy layer or Ni—Snalloy layer to decrease, and reductions in the resistance to pulling canbe inhibited. Further, reductions in the degree of resistance to pullingcan be inhibited, irrespective of the combinations of metals, exceptingNi and Sn, which are chosen.

In this context, an average thickness is set to less than 1.0 μm. If theaverage thickness exceeds 2.5 μm, in comparison with cases where thethickness of the Ni—Sn alloy layer is within the range mentioned above,the degree of rigidity is inferior. Although the rigidity as an Ni alloylayer, or an Ni—Sn alloy layer can still be secured, and the layers canbe used in normal circumstances, the level of resistance to pulling maydiminish.

As a result of experiments, it has been discovered that by adjusting thethickness of the Ni layer that serves as the composite layer, and theamount of the content of P therein, or the thickness of the Pd layer andthe amount of the content of P therein, the average thickness of the Nialloy layer, or of the Ni—Sn alloy layer, can be adjusted to 1.0-2.5 μm.In other words, if when the solder bump is formed, the composite layeris an Ni layer and Pd layer, or an Ni layer, Pd layer and precious metallayer, the Pd layer, or the Pd layer and precious metal layer, arediffused so as to form an Ni alloy layer or an Ni—Sn alloy layer. Atthis time, the thickness of the Ni alloy layer, or of the Ni—Sn alloylayer, can be adjusted by means of the thickness, and the amount of thecontent of P in the Ni layer, or by means of the thickness, and theamount of the content of P in the Pd layer. Thus, adjustment of thethickness of the Pd layer leads to a change in the thickness of theNi—Sn alloy layer. Consequently, reductions in the degree of therigidity of the Ni—Sn alloy layer can be inhibited and at the same time,reductions in the resistance to pulling can also be curbed.

An Ni alloy layer or an Ni—Sn alloy layer is constituted of particleshaving any one of shapes selected from among sheet-like bodies,column-like bodies and grain-like bodies. Such a layer may beconstituted of a single body selected from among them (for example,lamination in which only sheet-like bodies are laid on top of oneanother) or may also be of a compound structure thereof (for example,lamination in which sheet-like bodies and column-like bodies arecombined). An alloy layer constituted of mainly sheet-like bodies ispreferable. Sheet-like bodies allow for a gap to be formed between onesheet-like body and another and can be piled on top of one another.Thus, an alloy layer constituted of mainly sheet-like bodies can securea degree of rigidity easily, and can also easily secure a degree ofresistance to pulling relative to the solder. It is particularlypreferable for an alloy layer to be constituted of only sheet-likebodies.

The amount of the content of P (phosphor) in the Ni layer isparticularly preferably 0.5-15.0 wt %. If the amount of the content of Pis less than 0.5 wt %, or if it exceeds 15.0 wt %, formation of the Nilayer can easily be hampered. Further, promotion of the formation of thePd layer on the Ni layer can be hindered leading to defects such as afailure of the Pd layer to form errors in the formation of the Pb layer,or on occasions an appropriate degree of rigidity on the part of the Pblayer may not be secured. As a result, electric connectivity orreliability may on occasions not be secured. Although no problem occurswhen used as a printed wiring board for ordinary purposes, advantagescan accrue from the invention in a printed wiring board when long-termreliability is demanded.

The thickness of the nickel film, and the amount of the content ofphosphor in the nickel film can be adjusted by adjusting factors such asthe plating time, the plating temperature, the composition of theplating solution and the PH of the plating solution. Although variationscan occur, depending on the size of the bath used for the platingsolution, and the flow of the plating solution, it is preferable to seeka correlation with the thickness on the basis of the initial conditions.

P (phosphor) is preferably contained in both the Ni layer and the Pdlayer. If phosphor is contained in both, an Ni alloy layer, or an Ni—Snalloy layer, becomes easy to form and in consequence, it becomes moredifficult for the degree of rigidity of the solder bump in the solderpad, or in the alloy layer formed in the solder layer, to deteriorate.

The amount of the content of P (phosphor) in the Ni layer is preferablylower than the amount of the content of P (phosphor) in the Pd layer. Inconsequence, the Ni layer becomes covered with the Pd layer andseparation becomes less likely to be induced in an interface between thePd layer and the Ni layer. As a result, reductions in the degree ofelectric connectivity and reliability, resulting from defects in theinterface of the solder pad, never occur.

The amount of the content of P (phosphor) in the Ni layer is preferablyhigher than the amount of the content of P (phosphor) in the Pd layer.In consequence, when an alloy layer is formed by heat treatment of thePd layer and the Ni layer by means of a solder, it is likely to turninto a sheet-like body and consequently, it becomes easier to secure adesired, or greater degree of rigidity in the solder pad.

If, for example, a Pd layer is used in the intermediate layer, the Pdlayer (palladium layer) can inhibit the occurrence of defects such asthe phenomenon of a repellent solder. Thus, in comparison with aconventional solder pad structure, adhesiveness with solder can beenhanced.

The reasons for this are that palladium formed by plating rarely suffersfrom defects such as deposition failure, and that in terms of theformation of oxide film the ratio of the front surface of the palladiumlayer is less than in the case of an Au layer (gold layer). Thus,defects such as the repelling of a solder are induced less frequently,even when a solder is mounted. Further, a solder bump, or a solderlayer, of a desired size can be formed within the solder pad.Consequently, adhesiveness between the solder bump or the solder layerand the conductor circuit becomes less likely to diminish because asolder bump, or a solder layer, of a desired size can be formed to adesired size.

Use of the palladium layer facilitates buffering of thermal stress andconsequently, the frequency of defects in the solder bump, or in thesolder layer, can be reduced, thereby reducing the possibility ofdeteriorations in the degrees of electric connectivity and reliability.

The reason for this is that the palladium layer has a superior degree ofrigidity to that of gold. Thus, thermal stress can be absorbed withinthe Pd layer and buffered. Consequently, frequency of transmission ofstress to the solder bump, or to the solder layer, by means of thermalstress, can be reduced. Thus, the solder bump or the solder layer isunlikely to be damaged. Thus, defects in electric connections stemmingfrom the solder bump, or from the solder layer, become less likely to beinduced, and even when reliability tests are performed, long-termreliability can be secured.

Effects of this kind become more pronounced if a solder containing nolead (lead free) is used in the solder bump, or in the solder layer. Asolder that is free of lead is inferior to a solder containing lead interms of the buffering of thermal stress. In the first place, a soldercontaining lead (for example, Sn/Pd=6:4) buffers stress in the solderconcomitantly with the thermal stress generated. The reason for this isthat the lead contained in the solder absorbs stress. However, a solderthat is free of lead is inferior to a solder containing lead in terms ofa force for buffering stress. Thus, by providing a solder pad with acomposite layer composed of an Ni layer and a Pd layer, stress can bebuffered throughout the entire solder pad structure. Consequently,adhesiveness of the solder itself is superior to that in a conventionalsolder pad structure (Ni layer-Au layer), and since stress relative tothermal stress can be buffered more easily, defects, such as destructionand cracking in a solder bump or in a solder layer, that is formed, canbe curbed. Thus, this invention can secure degrees of electricconnectivity and reliability that are higher than in the case of a typein which a solder that is free of lead is applied to a conventionalsolder pad structure.

The thickness of an alloy layer including an Ni alloy layer can becontrolled by means of the amount of the content of phosphor (P) in thePd layer. The amount of P content in the Pd layer is preferably 2-7 wt%. Consequently, an intermediate layer that is formed is unlikely to beporous and the thickness of the film is likely to be uniform.Consequently, an alloy layer such as an Ni alloy layer can be formedeasily so that a degree of rigidity of the Ni alloy layer is easy tosecure.

If a Pd layer is used for an intermediate layer, the amount of thecontent of P is preferably 2-7 wt %. If the amount of the content of Pin the Pd layer is set within this range, the Pd layer formed isunlikely to be porous and the thickness of the film is likely to beuniform. Consequently, an Ni alloy layer becomes easy to form andbecause the aforementioned range of thickness can be secured, a degreeof rigidity of the Ni alloy layer becomes easiest to secure.

If the amount of the content of P in the Pd layer is less than 2% or ifthe amount of the content of P in the Pd layer exceeds 7%, the Pd layercannot be applied to the Ni layer uniformly and pores will remain in thePd layer. Although a thick Ni alloy layer becomes likely to be formedand in consequence, an Ni alloy layer that is formed can perform itsfunctions, it does become more difficult to enhance further a degree ofrigidity. As an extreme example, the average thickness of an Ni alloylayer can sometimes exceed 2.5 μm.

Further, the degree of rigidity of the Pd layer may on occasionsdeteriorate, thereby inhibiting the buffering of thermal stress. Thus,stress may on occasions be concentrated on the solder bump, or on thesolder layer, thus making more likely defects such as damage or crackingin the solder. Further if reliability tests are performed, it can onoccasions become difficult to secure reliability over a prolongedperiod.

It is desirable that a corrosion resistant layer be provided on anintermediate layer of the composite layer. The reason for this is thatprovision of such a corrosion resistant layer enables an intermediatelayer play a role in promoting the formation of an Ni alloy layer on theNi layer.

If a Pd layer is used as an intermediate layer of the composite layer,it is desirable to provide a corrosion resistant layer on the Pd layer.The reason for this is that provision of a corrosion resistant layerenables it to play a role of promoting the formation of an Ni alloylayer on the Ni layer.

In this context, a corrosion resistant layer is preferably formed of atleast one of precious metals selected from among precious metals such asAu, Ag, Pt and Sn. The reason for this is that use of these metalspromotes the formation of the Ni alloy layer.

The corrosion resistant layer may further be formed in two stages, bydisplacement plating with the same metal, by electroless plating or by acombination of displacement plating and electroless plating.Consequently, a metal film is formed that is not affected by the Nilayer which serves as a lower layer and corrosion resistance isaccordingly improved, adverse effects on the shape and the functioningof the solder bump can in consequence be mitigated.

It has been discovered that if a corrosion resistant layer is formed ofAu, the solder pad that is formed can vary, depending on the ratio of Auused and that in consequence the corrosion resistant property, theadhesiveness of the solder pad, and the shape and the functioning of thesolder bump can be enhanced.

The thickness of the corrosion resistant is preferably formed within arange of 0.01-2 μm. It is particularly preferable that the thickness beformed within a range of 0.03-1 μm. If the thickness of the corrosionresistant layer is less than 0.01 μm, formation of the alloy layer isnot in some cases promoted in local areas even when an Ni alloy layer isformed. Thus, an Ni alloy layer may in some cases not be formed in localareas and in consequence it becomes more difficult to enhance therigidity of the Ni alloy layer. As a result, improvements in resistanceof the Ni alloy layer peeling become less easy to obtain. However, nospecial problems occurred in the functioning, performance andreliability of a printed wiring board which is used in a normal way. Incontrast, if the thickness of the corrosion resistant layer exceeds 2μm, the promotion of the formation of the Ni alloy layer may onoccasions be hindered by that thickness. Thus, areas may occur in whichno Ni alloy layer is formed and in which, it thus becomes difficult toenhance the degree of rigidity of the Ni alloy layer. In consequence, itbecomes more difficult to raise the level of resistance of the Ni alloylayer to peeling.

In a three-layer structure of an Ni layer, an intermediate layer and acorrosion resistant layer, it has been discovered that the Ni layer andthe intermediate layer exercise most influence on the formation of theNi alloy layer, followed by the corrosion resistant layer. The presenceor otherwise of the corrosion resistant layer has had less influence onthe formation of the alloy layer.

An Ni layer constituting the composite layer of the present invention ispreferably formed of an alloy metal containing elements such as Ni—Cu,Ni—P, and Ni—Cu—P.

If an Ni layer is formed of a pure Ni film, its plating films need notnecessarily be overlaid in all directions, and for this reason finepores (defects) may on occasions occur. The reason for this is that inthe case of an alloy metal, a film is formed evenly by filling in pores.An Ni layer (intermediate)-Pd layer, or an Ni layer-Pd layer-corrosionresistant layer may be formed either physically or chemically, or by acombination of the two methods. Further, such layers may be formed as asingle layer, or as two or more layers.

It is particularly preferable that an Ni layer be formed of an alloymetal made up of Ni—P, or of Ni—Cu—P. In other words, the Ni layershould preferably contain P(phosphor). A further reason for this is thateven if instances of unevenness are formed on the surface of theconductor circuit, a film with a flattened front layer can be formed bykilling those instances of unevenness. Further, if the Ni layer isformed by plating, instances of non-formation of the metal layer, or oferrors in the formation of the metal layer caused by non-deposition orby halts in reaction are unlikely to occur in the Ni layer formed.

The conductor circuit on the outermost layer is covered and protected bya solder resist layer.

After a solder resist layer has been formed, a composite layer made upof an Ni layer and a Pd layer, or an Ni layer, an intermediate layer anda corrosion resistant layer, is formed in the portion surrounding theopening.

As an example, a metal layer containing Ni can be formed by electrolessplating on a conductor circuit exposed from the solder pad. As anexample of a composition of a plating solution, nickel sulfate of 4.5g/l, sodium hypophosphite of 25 g/l, sodium citrate of 40 g/l, boracicacid of 12 g/l and thiouric acid of 0.1 g/l (PH=11) are available. Theposition of the solder resist layer surrounding the opening and thesurface can be washed with a degreasing solution, and a catalyst such aspalladium can be applied to a conductor portion exposed in the portionsurrounding the opening so as to activate it and then, by dipping in theplating solution, a nickel plating layer can be formed.

After the nickel layer has been formed, an intermediate layer (forexample, a Pd layer) can be formed on the Ni layer. Next, a corrosionresistant layer is formed of a metal selected from among Au, Ag, Pt andSn. It is particularly preferable that the corrosion resistant layer beformed of gold. Depending on the circumstances, two layers may beformed, by means of displacement plating with the same metal, and bymeans of electroless plating. The thickness is preferably 0.01-2μ.

After the corrosion resistant layer has been applied in the portionsurrounding the opening so as to form the solder pad, solder paste of atwo-component base solder, a three-component base solder or amulti-component base solder is applied onto the portion surrounding theopening by means of printing. Thereafter, the board is passed throughnitrogen reflow at a temperature of 250-350° C. so as to fix the solderbump to the solder pad in the portion surrounding the opening.

The solder layer is formed on the solder pad on the external connectingterminal side, and the external connecting terminal (BGA, PGA or thelike) is loaded onto the solder layer.

Although the present invention is applied to a build-up printed wiringboard, and to a subtraction multilayered board, the same effects can beexpected when it is applied to various boards such as a single facecircuit board, to a double face circuit board, to a flexible board,flexible board in which a reel-to-reel method is used to a ceramic boardand to a AIN board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a multilayered printed wiring boardaccording to a first embodiment of the present invention.

FIG. 2 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the first embodiment of the presentinvention.

FIG. 3 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the first embodiment of the presentinvention.

FIG. 4 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the first embodiment of the presentinvention.

FIG. 5 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the first embodiment of the presentinvention.

FIG. 6 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the first embodiment of the presentinvention.

FIG. 7 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the first embodiment of the presentinvention.

FIG. 8(A) is a schematic diagram illustrating the circular portion A inFIG. 7(B) in an enlarged form, and FIG. 8(B) is a schematic diagramillustrating the circular portion B in FIG. 1 in an enlarged form.

FIG. 9 is a sectional view of the multilayered printed wiring boardaccording to a second embodiment of the present invention.

FIG. 10 is a diagram of a manufacturing process of the printed wiringboard according to the second embodiment.

FIG. 11 is a diagram of a manufacturing process of the printed wiringboard according to the second embodiment.

FIG. 12 is a diagram of a manufacturing process of the printed wiringboard according to the second embodiment.

FIG. 13 is a diagram of a manufacturing process of the printed wiringboard according to the second embodiment.

FIG. 14(A) is a schematic diagram illustrating the circular portion A inFIG. 12(B) in an enlarged form and FIG. 14(B) is a schematic diagramillustrating the circular portion B in FIG. 9 in an enlarged form.

FIG. 15 contains electron microscopic pictures of a nickel layer, aCu—Ni—Sn alloy layer and a solder.

FIG. 16 contains electron microscopic pictures of a Cu—Ni—Sn alloylayer.

FIG. 17 contains electron microscopic pictures of a Cu—Ni—Sn alloylayer.

FIG. 18 contains transmission type electron microscopic pictures of aCu—Ni—Sn alloy layer.

FIG. 19 is an electron microscopic picture of a Pd layer of 0.7 μm inthickness.

FIG. 20 is an electron microscopic picture of a Pd layer of 0.3 μm inthickness.

FIG. 21 is a sectional view of the multilayered printed wiring boardaccording to a third embodiment of the present invention.

FIG. 22 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the third embodiment.

FIG. 23 is a diagram of a manufacturing process of the multilayeredprinted wiring board according to the third embodiment.

FIG. 24(A) is a schematic diagram illustrating the circular portion A inFIG. 23(B) in an enlarged form and FIG. 24(B) is a schematic diagramillustrating the circular portion A in FIG. 21 in an enlarged form.

FIG. 25 is a sectional view of the multilayered printed wiring boardaccording to a fourth embodiment of the present invention.

FIG. 26 is a diagram of a manufacturing process of the printed wiringboard according to the fourth embodiment.

FIG. 27 is a diagram of a manufacturing process of the printed wiringboard according to the fourth embodiment.

FIG. 28 is a diagram of a manufacturing process of the printed wiringboard according to the fourth embodiment.

FIG. 29(A) is a schematic diagram illustrating the circular portion B inFIG. 29(A) in an enlarged form and FIG. 29(B) is a schematic diagramillustrating the circular portion A in FIG. 27 in an enlarged form.

FIGS. 30(A), 30(B) are schematic diagrams illustrating the formation ofa Pd film, FIG. 30(A) illustrates a case where P is provided while FIG.30(B) illustrates a case where no P is provided.

FIG. 31 is a table showing parameters of the first embodiment.

FIG. 32 is a table showing parameters of the first embodiment.

FIG. 33 is a table showing parameters of the first embodiment.

FIG. 34 is a table showing parameters of the second embodiment.

FIG. 35 is a table showing parameters of the second embodiment.

FIG. 36 is a table showing parameters of the second embodiment.

FIG. 37 is a table showing parameters of a first reference example.

FIG. 38 is a table showing parameters of a second reference example.

FIG. 39 is a table showing parameters of the third embodiment.

FIG. 40 is a table showing parameters of the third embodiment.

FIG. 41 is a table showing parameters of the third embodiment.

FIG. 42 is a table showing parameters of the fourth embodiment.

FIG. 43 is a table showing parameters of the fourth embodiment.

FIG. 44 is a table showing parameters of the fourth embodiment.

FIG. 45 is a table showing parameters of a third reference example.

FIG. 46 is a table showing parameters of a fourth reference example.

FIG. 47 is a table showing parameters of a comparative example.

FIG. 48 is a table showing test results of the first embodiment.

FIG. 49 is a table showing test results of the first embodiment.

FIG. 50 is a table showing test results of the first embodiment.

FIG. 51 is a table showing test results of the second embodiment.

FIG. 52 is a table showing test results of the second embodiment.

FIG. 53 is a table showing test results of the second embodiment.

FIG. 54 is a table showing test results of the first reference example.

FIG. 55 is a table showing test results of the second reference example.

FIG. 56 is a table showing test results of the third reference example.

FIG. 57 is a table showing test results of the third reference example.

FIG. 58 is a table showing test results of the third reference example.

FIG. 59 is a table showing test results of the fourth embodiment.

FIG. 60 is a table showing test results of the fourth embodiment.

FIG. 61 is a table showing test results of the fourth embodiment.

FIG. 62 is a table showing test results of the third reference example.

FIG. 63 is a table showing test results of the fourth reference example.

FIG. 64 is a table showing test results of the comparative example.

FIG. 65 is a graph showing a correlation between palladium thickness andstrength.

FIG. 66 is a graph showing a correlation between the amount of thecontent of phosphor in palladium and strength.

FIG. 67 is a graph showing a correlation between nickel thickness andstrength.

FIG. 68 is a graph showing a correlation between the amount of thecontent of phosphor in nickel and strength.

FIG. 69 is a graph showing results of simulation of pulling resistancefor thicknesses of a Ni—Sn alloy layer.

FIG. 70 is a graph showing a correlation between thickness of acorrosion resistant layer and strength.

BEST MODES FOR CARRYING OUT THE INVENTION Embodiment 1

The configuration of a multilayer printed wiring board 10 according toEmbodiment 1 of the present invention will first be described withreference to FIG. 1 showing the cross section thereof. The multilayerprinted wiring board 10 has a conductor circuit 34 formed on the frontsurface of a core substrate 30. The front and rear surfaces of the coresubstrate 30 are connected to each other via through holes 36. Inaddition, an interlayer resin insulating layer 50 on which via holes 60and conductor circuits 58 are formed and an interlayer resin insulatinglayer 150 on which via holes 160 and conductor circuits 158 are formedare provided on the both surfaces of the core substrate 30. Solderresist layers 70 are formed on upper layers of the via holes 160 and theconductor circuits 158, and solder pads 77U and 77D are formed on theconductor circuits 158 through the opening portions 71 of the solderresist layers 70, respectively. Bumps 76U and 76D are formed on thesolder pads 77U and 77D.

Next, the solder pads 76U will be described with referring to FIG. 8.FIG. 8(B) enlarged shows circle A part of multilayer printed circuitboard 10 in FIG. 1. Nickel plated layer 72 is formed on conductorcircuit 158. The conductor circuit 158 is connected to solder layer(bump) 46 via Ni—Sn alloy layer 75 on nickel plated layer 72. Inembodiment 1, by controlling the average thickness of Ni—Sn alloy layer75, the occurrence of the breakage in the interface between the nickelplated layers 72 and the solder layer 46 can be reduced. Thereby, thestrength and adhesion of solder layer 46 can be improved.

A method for manufacturing the multilayer printed wiring board 10described above will next be described with reference to FIGS. 2 to 8.

A. Manufacturing of resin film of interlayer resin insulating layer 30parts by weight of bisphenol A type epoxy resin (epoxy equivalent weightof 469, Epicoat 1001 manufactured by Yuka Shell Epoxy), 40 parts byweight of cresol novolac type epoxy resin (epoxy equivalent weight of215, EpiclonN-673 manufactured by Dainippon Ink and Chemicals) and 30parts by weight of phenol novolac resin including a triazine structure(phenol hydroxyl group equivalent weight of 120, PhenoliteKA-7052manufactured by Dainippon Ink and Chemicals) are heated and molten whilebeing agitated with 20 parts by weight of ethyl diglycol acetate and 20parts by weight of solvent naphtha, and 15 parts by weight of terminallyepoxidized polybutadiene rubber (DenalexR-45EPT manufactured by NagaseChemicals Ltd.) and 1.5 parts by weight of crushed product of2-phenyl-4,5-bis(hydroxymethyl) imidazole, 2 parts by weight ofpulverized silica and 0.5 parts by weight of silicon-based defoamingagent are added thereto, thereby preparing an epoxy resin composition.

The obtained epoxy resin composition is coated on a PET film having athickness of 38 μm so as to have a thickness of 50 μm after being driedby a roll coater and dried for 10 minutes at 80 to 120° C., therebymanufacturing a resin film for an interlayer resin insulating layer.

B. Preparation of Resin Filler

100 parts by weight of bisphenol F type epoxy monomer (manufactured byYuka Shell, molecular weight: 310, YL983U), 170 parts by weight of SiO₂spheroidal particles having a silane coupling agent coated on surfacesthereof, a mean particle size of 1.6 μm, and a largest particle size ofnot more than 15 μm (manufactured by ADTEC Corporation, CRS 1101-CE) and1.5 parts by weight of leveling agent (manufactured by Sannopuko KK,PelenolS4) are input in a container and agitated and mixed therein,thereby preparing resin filler having a viscosity of 44 to 49 Pa·s at23±1° C. As hardening agent, 6.5 parts by weight of imidazole hardeningagent (manufactured by Shikoku Chemicals, 2E4MZ-CN) is used. As theresin filler, thermosetting resin such as the other epoxy resin (e.g.,bisphenol A type, novolac type or the like), polyimide resin or phenolresin may be used.

C. Manufacturing of Multilayer Printed Wiring Board

-   (1) A copper-clad laminate 30A having 18 μm copper foils 32    laminated on the both surfaces of a 0.8 mm insulative substrate 30    made of glass epoxy resin or BT (Bismaleimide-Triazine) resin,    respectively, is used as a starting material (FIG. 2(A)). First,    this copper-clad laminate 30A is drilled, subjected to an    electroless plating treatment and an electroplating treatment, and    etched into a pattern to thereby form lower layer conductor circuits    34 on the both surfaces of the substrate, and through holes 36 (FIG.    2(B)).-   (2) After washing and drying the substrate having the through holes    and the lower layer conductor circuits formed thereon, an    oxidization treatment using an aqueous solution containing NaOH (10    g/l), NaClO2 (40 g/l) and Na3PO4 (6 g/l) as a blackening bath (an    oxidation bath) and a reduction treatment using an aqueous solution    containing NaOH (10 g/l) and NaBH4 (6 g/l) as a reduction bath are    conducted to the substrate 30, thereby respectively forming    roughened surfaces 36α, 34α on the entire surfaces of the conductor    circuits 34 including through holes 36 (FIG. 2(C)).-   (3) After preparing the resin filler described in B above, within 24    hours of preparation, according to the following method, layers of    the resin filler 40 are formed in the through holes 36 and on the    lower layer conductor circuits unformed portions and outer edges of    the one side of substrate.

Namely, a resin filling mask having openings in portions correspondingto the through holes 36 and the lower layer conductor circuit 34unformed portions is put on the substrate, and the resin filler 40 isfilled into the through holes, depressed the lower layer conductorcircuits unformed portions and the outer edges of the lower layerconductor circuits with a squeegee and then dried at 100° C. for 20minutes (FIG. 2(D)).

-   (4) One of the surfaces of the substrate which has been subjected to    the treatment of (3) is polished by belt sander polishing using #600    belt abrasive paper (manufactured by Sankyo Rikagaku Co.) so as not    to leave the resin filler 40 on the outer edges of the lower layer    conductor layers 34 and those of the lands of the through holes 36,    and the entire surfaces of the lower layer conductor layers 34    (including the land surfaces of the through holes) are then buffed    to remove scratches caused by the belt sander polishing. A series of    these polishing treatments are similarly conducted to the other    surface of the substrate. The resin filler 40 is then heated at    100° C. for 1 hour and at 150° C. for 1 hour and hardened (FIG.    3(A)).

As a result, a substrate in which the surface layer portions of theresin fillers 40 formed in the through holes 36 and on the conductorcircuit unformed portions and the surfaces of the lower layer conductorlayers 34 are flattened, the resin fillers 40 are fixedly attached tothe side surfaces of lower layer conductor layers 34 through theroughened surfaces and the inner wall surfaces of the through holes 36are fixedly attached to the resin fillers through the roughenedsurfaces, is obtained. That is to say, through the steps, the surfacesof the resin fillers become almost flush with those of the lower layerconductor circuits.

-   (5) After washing and acid-degreasing the substrate, soft etching is    conducted to the substrate and etchant is sprayed onto the both    surfaces thereof to etch the surfaces of the lower layer conductor    circuits 34, and the land surfaces of the through holes 36, thereby    forming roughened surfaces 36β on the entire surfaces of the    respective lower layer conductor circuits 34 (see FIG. 3(B)). As the    etchant, etchant (manufactured by Mech Corporation, Mech-Etch Bond)    comprising 10 parts by weight of an imidazole copper (II) complex, 7    parts by weight of glycolic acid and 5 parts by weight of potassium    chloride is used.-   (6) Interlayer resin insulating layer resin films slightly larger    than the substrate manufactured in A are put on the both surfaces of    the substrate, respectively, temporarily press-fitted under    conditions of pressure of 0.4 MPa, a temperature of 80° C. and    press-fit time of 10 seconds and cut, and then bonded using a vacuum    laminator by the following method, thereby forming interlayer resin    insulating layers 50 (FIG. 3(C)). Namely, the interlayer resin    insulating layer resin films are actually press-fitted onto the    substrate under conditions of vacuum of 67 Pa, pressure of 0.4 MPa,    a temperature of 80° C. and press-fit time of 60 seconds, and then    thermally hardened at 170° C. for 30 minutes.-   (7) Next, through a mask having pass-through holes having a    thickness of 1.2 mm formed therein, openings 50 a for via holes are    formed to have a diameter of 80 μm in the interlayer resin    insulating layers 50 by a CO2 gas laser at a wavelength of 10.4 μm    under conditions of a beam diameter of 4.0 mm, a top hat mode, a    pulse width of 8.0 microseconds, the pass-through hole diameter of    the mask of 1.0 mm and one shot (FIG. 3(D)).-   (8) The substrate having the via hole openings 50 a formed therein    is immersed in a solution containing 60 g/l of permanganic acid at a    temperature of 80° C. for 10 minutes to melt and remove epoxy resin    particles existing on the surfaces of the interlayer resin    insulating layers 50, thereby forming roughened surfaces on the    surfaces of the respective interlayer resin insulating layers 50    including the inner walls of the via hole openings 50 a (FIG. 3(E)).-   (9) Next, the substrate which has been subjected to the above-stated    treatments is immersed in neutralizer (manufactured by Shipley    Corporation) and then washed. Further, a palladium catalyst is added    to the surfaces of the roughened substrate (a roughening depth of 3    μm), thereby attaching catalyst nuclei to the surfaces of the    interlayer resin insulating layers 50 and the inner wall surfaces of    the via hole openings 50 a (Not shown in Figures). Namely, the    substrate is immersed in a catalytic solution containing palladium    chloride (PbCl2) and stannous chloride (SnCl2) and palladium metal    is precipitated, thereby attaching the catalyst.-   (10) The substrate to which the catalyst is attached is immersed in    an electroless copper plating aqueous solution having the following    composition and electroless copper plated films having a thickness    of 0.6 to 3.0 μm are formed on the entire roughened surfaces,    thereby obtaining the substrate having electroless copper plated    films 52 formed on the surfaces of the interlayer resin insulating    layers 50 including the inner walls of the via hole openings 50 a    (FIG. 4(A)).

[Electroless Plating Aqueous Solution]

NiSO4 0.003 mol/l Tartaric acid 0.200 mol/l Copper sulfate 0.030 mol/lHCHO 0.050 mol/l NaOH 0.100 mol/l α,α′-bipyridyl 100 mg/l Polyethyleneglycol (PEG) 0.10 g/l[Electroless Plating Conditions]40 minutes and a solution temperature of 34° C.

-   (11) Commercially available sensitive dry films are bonded to the    substrate on which the electroless copper plated films 52 are    formed, a mask is put on the substrate, the substrate is exposed at    100 mJ/cm² and developed with a 0.8% sodium carbonate aqueous    solution, thereby providing plating resists 54 having a thickness of    20 μm (FIG. 4(B)).-   (12) Next, the substrate is cleaned and degreased with water at 50°    C., washed with water at 25° C., cleaned with sulfuric acid and    electroplated under the following conditions.

[Electroplating Solution]

Sulfuric acid 2.24 mol/l Copper sulfate 0.26 mol/l Additive (KalapacidGL 19.5 ml/l manufactured by Atotech Japan)

[Electroplating Conditions]

Current density 1 A/dm² Time 65 minutes Temperature 22 ± 2° C.

Thereby forming electroplated copper films 56 having a thickness of 20μm on portions on which the plating resists 54 are not formed (FIG.4(C)).

-   (13) After peeling off the plating resists 54 with 5% KOH, the    electroless plated films 52 under the plating resist 54 are etched,    molten and removed with a solution mixture of sulfuric acid and    hydrogen peroxide, thus forming independent upper layer conductor    circuits 58 and via holes 60 (FIG. 4(D)).-   (14) The same treatment as that of (5) is performed to form    roughened surfaces 58α and 60α on the surfaces of the conductor    circuits 58 and the via holes 60 (FIG. 4(A)).-   (15) The steps (6) to (14) stated above are repeated, thereby    forming further upper layer interlayer resin insulating layers 150    having conductor circuits 158 and via holes 160, and a multilayer    wiring board is obtained (FIG. 5(B)).-   (16) Next, 46.67 parts by weight of oligomer (molecular    weight: 4000) which is obtained by forming 50% of epoxy groups of 60    parts by weight of cresol novolac type epoxy resin (manufactured by    Nippon Kayaku Co., Ltd.) dissolved in diethylene glycol dimethyl    ether (DMDG) into an acrylic structure and which imparts    photosensitive characteristic, 15.0 parts by weight of 80 wt % of    bisphenol A type epoxy resin (manufactured by Yuka Shell, product    name: Epicoat 1001) dissolved in methylethyl ketone, 1.6 parts by    weight of imidazole hardening agent (manufactured by Shikoku    Chemicals, product name: 2E4MZ-CN), 4.5 parts by weight of    bifunctional acryl monomer which is photosensitive monomer    (manufactured by Kyoei Chemical, product name: R604), 1.5 parts by    weight of polyhydric acryl monomer (manufactured by Kyoei Chemical,    product name: DPE6A), and 0.71 parts by weight of dispersing    defoaming agent (manufactured by Sannopuko KK, product name: S-65)    are input in the container, agitated and mixed to prepare a mixture    composition. 2.0 parts by weight of benzophenone (manufactured by    Kanto Chemical) serving as photoinitiator and 0.2 parts by weight of    Michler's ketone (manufactured by Kanto Chemical) serving as    photosensitizer are added to the mixture composition, thereby    obtaining a solder resist composition adjusted to have a viscosity    of 2.0 Pa·s at 25° C.

The viscosity is measured by using the No. 4 rotor of a B-typeviscometer (manufactured by Tokyo Keiki, DVL-B type) when the velocityis 60 min-l, and using the No. 3 rotor thereof when the velocity is 6min-l.

-   (17) Next, after the above-stated solder resist composition 70 is    coated on each surface of the multilayer wiring board by a thickness    of 30 μm (FIG. 5(C)), and dried under conditions of 70° C. for 20    minutes and 70° C. for 30 minutes, a photomask on which a pattern of    solder resist opening portions are drawn and which has a thickness    of 5 mm, is fixedly attached to each solder resist layer 70, exposed    with ultraviolet rays of 800 mJ/cm², and developed with a DMTG    solution, thereby forming opening portions 71 having a diameter of    150 μm (FIG. 6(A)).

Further, heat treatments are conducted at 100° C. for 1 hour, and at150° C. for 3 hours, respectively, to harden the solder resist layers,thus forming solder resist layers 20 each having opening portions and athickness of 20 μm. As the solder resist composition, a commerciallyavailable solder resist composition can be also used.

-   (18) Next, nickel plated layers are formed on the solder pads of the    substrate having the solder resist layers 70.

[Nickel Plating Aqueous Solution]

nickel chloride 2.3 × 10⁻¹ mol/l sodium hypophosphite 1.8 to 4.0 × 10⁻¹mol/l sodium citrate 1.6 × 10⁻¹ mol/l pH of 4.5 temperature of 40 to 60°C.

The substrate is immersed in the electroless nickel plating solution for5 to 40 minutes, thereby forming nickel plated layers 72 in the openingportions 71 (FIG. 6(B)). In the Embodiment 1, nickel plated layers 72are adjusted so as to have a thickness of 0.03 to 10 μm, to include 0.4to 17 wt % of P. The thickness and the P content of the nickel platedlayers are adjusted in considering the value of a plating tub andplating solution circulation.

-   (19) Thereafter, palladium layers are formed on the solder pads on    which the nickel plated layers have been formed in step (18) of the    substrate.

[Palladium Plating Aqueous Solution]

palladium chloride 1.0 × 10⁻² mol/l ethylenediamine 8.0 × 10⁻² mol/lsodium hypophosphite 4.0 to 6.0 × 10⁻² mol/l thiodiglycolic acid 30 mg/lpH of 8 temperature of 50 to 60° C.

The substrate is immersed in the electroless palladium plating solutionfor 3 to 10 minutes, thereby forming palladium plated layers 73 having athickness of 0.08 μm on the nickel plated layers 72 (FIG. 7(A)). In theEmbodiment 1, palladium plated layers 73 are adjusted so as to have athickness of 0.008 to 2.0 μm, to include 1 to 8 wt % of P. The thicknessand the P content of the palladium plated layers are adjusted inconsidering the value of a plating tub and plating solution circulation.

-   (20) Solder paste 76 a is printed on solder pads 77U, 77D in each    opening 71 of the solder resist layer 70 (FIG. 7(B)). The solder pad    77U in the circle A in FIG. 7(B) is enlarged shown in FIG. 8(A). The    solder pad 77U consists of the multi-layers, that is, the two layers    comprise nickel plated layers 72—palladium plated layers 73 which    have been formed in turn on the conductor circuit 158.-   (21) Thereafter, solder bumps 76U, 76D are formed by conducting    reflow at 250° C. in nitrogenous atmosphere (FIG. 1). The solder pad    77U in the circle B in FIG. 1 is enlarged shown in FIG. 8(B). During    the reflow, palladium plated layers 73 almost diffuse into solder    bumps 76U, 76D, Cu—Ni—Sn alloy layer 75 or Ni layer alloy layer is    formed in the interface between nickel plated layers 72 and solder    bumps 76U, 76D as shown in FIG. 1 and FIG. 8(B).

Here, the nickel plated layers 72 is adjusted so as to have thethickness of 0.05 to 7 μm and the P content is adjusted to 0.4 to 17 wt% which is lower or higher than thereof the palladium layers. And thepalladium plated layers 73 is adjusted so as to have thickness of 0.01to 1.0 μm and the P content is adjusted to 2 to 7 wt %. Thereby, theaverage thickness of Cu—Ni—Sn alloy layer 75 is controlled between 1.0and 2.5 μm.

Embodiment 1-1-1

In embodiment 1-1-1, an alloy of Cu: 0.5 wt %, Ag: 3.5 wt %, Sn: 95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 5 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.5 μm. Electron microscope pictures of Ni layer, Cu—Ni—Sn alloyand solder in embodiment 1-1-1 are shown in FIGS. 15-18. The electronmicroscope picture (×20 k) in the left side of FIG. 15 shows embodiment1-1-1. The electron microscope pictures (×100 k) in the left sides ofFIGS. 16, 17 are a more enlarged scale. The right sides of electronmicroscope pictures in FIGS. 15, 16, 17 show Pd layers which do notcontain P in reference example 1-1-1. The lower side is the Ni layer andthe upper side is the solder and the interface between the Ni layer andthe solder is the Cu—Ni—Sn alloy. As shown in the electron microscopepicture in the left side of FIG. 15, in embodiment 1-1-1, the Cu—Ni—Snalloy is consecutively formed on the surface of Ni layer, that is, isslightly Ups and downs. As shown in the electron microscope pictures inthe left sides of FIGS. 16, 17 using enlarged scale, Ag particlesuniformly exist on the surface of the Cu—Ni—Sn alloy through skin layerof Sn. In embodiment 1-1-1, as shown in the permeation type electronmicroscope picture in the right side of FIG. 18, the Ni—Cu—Sn alloylayer is typically a board-shaped form, that is, formed in parallel withthe Ni layer.

Embodiment 1-1-2

In embodiment 1-1-2, an alloy of Cu: 0.5 wt %, Ag: 3.5 wt %, Sn: 95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 1-1-3

In embodiment 1-1-3, an alloy of Cu: 0.5 wt %, Ag: 3.5 wt %, Sn: 95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 1-1-4

In embodiment 1-1-4, an alloy of Cu: 0.5 wt %, Ag: 3.5 wt %, Sn: 95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-5

In embodiment 1-1-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-6

In embodiment 1-1-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 0.01 μm, P content 7 wt %. Therefore, the composition ofthe Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-7

In embodiment 1-1-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-8

In embodiment 1-1-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 3 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.8 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-9

In embodiment 1-1-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-10

In embodiment 1-1-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37: 21, the thicknessbecomes 1.6 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-11

In embodiment 1-1-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-12

In embodiment 1-1-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.6 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-13

In embodiment 1-1-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-14

In embodiment 1-1-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 7 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-15

In embodiment 1-1-15, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 5 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-16

In embodiment 1-1-16, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-17

In embodiment 1-1-17, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 10 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.8 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-18

In embodiment 1-1-18, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 10 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 5 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-19

In embodiment 1-1-19, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 2.0 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-20

In embodiment 1-1-20, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 15 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 2 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.9μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-21

In embodiment 1-1-21, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 8 μm, P content 15 wt %. On the other hand, Pd layer is formedas thickness 0.01 μm, P content 7 wt %. Therefore, the composition ofthe Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes2.0 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-1-22

In embodiment 1-1-22, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 2.1 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 1-2-1

In embodiments 1-1-1 to 1-1-20, the Cu/Ag/Sn solder which does notinclude lead is used as the solder consisting of the solder bump.Whereas, in embodiment 1-2-1, an alloy of Sn:Pb=63:37 (wt %) is used asa solder consisting of the solder bump. Ni layer is formed as thickness5 μm, P content 1.2 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 5 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. TheNi—Sn alloy layer is typically a board-shaped form.

Embodiment 1-2-2

In embodiment 1-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 0.0μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-3

In embodiment 1-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-4

In embodiment 1-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-5

In embodiment 1-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-6

In embodiment 1-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 0.0μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-7

In embodiment 1-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-8

In embodiment 1-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 3 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-9

In embodiment 1-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 0.0μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-10

In embodiment 1-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-11

In embodiment 1-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-12

In embodiment 1-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Ni=67:33, the thickness becomes 1.6 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 1-2-13

In embodiment 1-2-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-14

In embodiment 1-2-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 1-2-15

In embodiment 1-2-15, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 8 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-16

In embodiment 1-2-16, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 8 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 1-2-17

In embodiment 1-2-17, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 10 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-18

In embodiment 1-2-18, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 10 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-19

In embodiment 1-2-19, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 15 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.9 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-20

In embodiment 1-2-20, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-21

In embodiment 1-2-21, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 8 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.0 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-2-22

In embodiment 1-2-22, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.2 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 1-3-1

In embodiment 1-3-1, the alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump same as embodiment1-1-1. Ni layer is formed as thickness 5 μm, P content 1.2 wt % as sameas embodiment 1-1-1. On the other hand, Pd layer is formed as thickness0.009 μm, P content 8 wt %. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. Inembodiment 1-3-1, as shown an electron microscope picture in the rightside of FIG. 18, the Ni—Cu—Sn alloy layer is typically a pillar-shapedform, that is, pillar-shaped alloy crystal vertically formed along withthe Ni layer as same as reference example 1-1-1 which will be explainedlater.

Embodiment 1-3-2

In embodiment 1-3-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.008 μm, P content 7 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:45:13, thethickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 1-3-3

In embodiment 1-3-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.009 μm, P content 1 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:45:13, thethickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 1-3-4

In embodiment 1-3-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-3-5

In embodiment 1-3-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 5 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped (grainycrystal) and formed at an interface of the Ni layer.

Embodiment 1-3-6

In embodiment 1-3-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 2.0 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.5μm. The Ni—Sn alloy layer is typically a grain-shaped and formed at aninterface of the Ni layer.

Embodiment 1-3-7

In embodiment 1-3-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.03 μm, P content 3 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, thethickness becomes 1.1 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 1-3-8

In embodiment 1-3-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.03 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-3-9

In embodiment 1-3-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.03 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-3-10

In embodiment 1-3-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.4 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-3-11

In embodiment 1-3-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.5 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-3-12

In embodiment 1-3-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 12 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes2.4 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-3-13

In embodiment 1-3-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 12 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 2 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes 2.5μm. The Ni—Sn alloy layer is typically a grain-shaped and formed at aninterface of the Ni layer.

Embodiment 1-3-14

In embodiment 1-3-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 12 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes2.4 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 1-4-1

In embodiment 1-4-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump, as same as embodiment 1-2-1. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.009 μm, P content 8 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 2.5 μm. The Ni—Sn alloy layer is typically a pillar-shaped form.

Embodiment 1-4-2

In embodiment 1-4-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.008 μm, P content 7 wt %. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Ni=67:33, the thickness becomes 2.5 μm. The Ni—Snalloy layer is typically a pillar-shaped form.

Embodiment 1-4-3

In embodiment 1-4-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.009 μm, P content 1 wt %. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Ni=67:33, the thickness becomes 2.5 μm. The Ni—Snalloy layer is typically a pillar-shaped form.

Embodiment 1-4-4

In embodiment 1-4-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-5

In embodiment 1-4-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-6

In embodiment 1-4-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 9 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-7

In embodiment 1-4-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.03 μm,P content 0.4 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 3 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.1 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-8

In embodiment 1-4-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.03 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-9

In embodiment 1-4-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.03 μm,P content 16 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-10

In embodiment 1-4-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness 0.2μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-11

In embodiment 1-4-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 16 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-12

In embodiment 1-4-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 12 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-4-13

In embodiment 1-4-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 12 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 2 wt %. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Ni=67:33, the thickness becomes 2.5 μm. The Ni—Sn alloy layeris typically a grain-shaped and formed at an interface of the Ni layer.

Embodiment 1-4-14

In embodiment 1-4-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 12 μm, Pcontent 17 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 1-5-1

In embodiment 1-5-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 0 wt %. (An electron microscope picture of the Pdlayer is shown in FIG. 19. As shown in the figure, Pd layer partlyseparates out, and under Ni layer can be seen via porous of the Pdlayer.) When the solder is conducted reflow, flux containing copper isused. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloy layeris typically a grain-shaped form.

Embodiment 1-5-2

In embodiment 1-5-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.07 μm, P content 5 wt %. (An electron microscope picture of the Pdlayer is shown in FIG. 20. As shown in the figure, Pd layer is uniformlyformed.) When the solder is conducted reflow, flux containing copper isused. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloy layeris typically a board-shaped form, as same as embodiment 1-1-1 which hasbeen referred with the electron microscope picture of the left side ofFIG. 18.

REFERENCE EXAMPLE 1-1-1

In reference examples 1-1-1 to 1-1-12 and reference examples 1-2-1 to1-2-12, a buildup-multi-layer-circuit-board is formed and a solder bumpis formed, as same as the above embodiment 1 which has been explainedwith referring to FIGS. 1-8.

In reference example 1-1-1, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=38:20:42, thethickness becomes 0.8 μm. Electron microscope pictures of Ni layer,Cu—Ni—Sn alloy and solder in reference example 1-1-1 are shown in FIGS.15-18. The electron microscope picture (×20 k) in the right side of FIG.15 shows reference example 1-1-1. The electron microscope pictures (×100k) in the right sides of FIGS. 16, 17 are a more enlarged scale. Thelower side is the Ni layer and the upper side is the solder and theinterface between the Ni layer and the solder is the Cu—Ni—Sn alloy. Asshown in the electron microscope picture in the right side of FIG. 15,in reference example 1-1-1, the Cu—Ni—Sn alloy is un-consecutivelyformed on the surface of Ni layer, that is, is Ups and downs. As shownin the electron microscope pictures in the right sides of FIGS. 16, 17using enlarged scale, Ag particles un-uniformly dotted exist on thesurface of the Cu—Ni—Sn alloy through skin layer of Sn. In referenceexample 1-1-1, as shown in the electron microscope picture in the rightside of FIG. 18, the Ni—Cu—Sn alloy layer is typically a pillar-shapedform, that is, pillar-shaped alloy crystal vertically formed along withthe Ni layer.

REFERENCE EXAMPLE 1-1-2

In reference example 1-1-2, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.0 μm, P content 0.8 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, thethickness becomes 0.9 μm.

REFERENCE EXAMPLE 1-1-3

In reference example 1-1-3, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 am, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.0 μm, P content 9 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.7 μm.

REFERENCE EXAMPLE 1-1-4

In reference example 1-1-4, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.5 μm, P content 9 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.9 μm.

REFERENCE EXAMPLE 1-1-5

In reference example 1-1-5, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=38:20:42, thethickness becomes 0.8 μm.

REFERENCE EXAMPLE 1-1-6

In reference example 1-1-6, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder bump. Ni layer is formedas thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 1-1-7

In reference example 1-1-7, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder bump. Ni layer is formedas thickness 0.03 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 9 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 1-1-8

In reference example 1-1-8, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder bump. Ni layer is formedas thickness 0.03 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1.5 μm, P content 9 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 1-1-9

In reference example 1-1-9, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder bump. Ni layer is formedas thickness 12 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 0 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, the thicknessbecomes 2.5 μm.

REFERENCE EXAMPLE 1-1-10

In reference example 1-1-10, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.6 μm.

REFERENCE EXAMPLE 1-1-11

In reference example 1-1-11, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 9 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.7 μm.

REFERENCE EXAMPLE 1-1-12

In reference example 1-1-12, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.9 μm.

REFERENCE EXAMPLE 1-2-1

In reference examples 1-1-1 to 1-1-12, the Cu/Ag/Sn solder which doesnot include lead is used as the solder consisting of the solder bump.Whereas, in reference examples 1-2-1 to 1-2-12, an alloy of Sn:Pb=63:37(wt %) is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 1-2-2

In reference example 1-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 0.8 wt %. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 1-2-3

In reference example 1-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 9 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 1-2-4

In reference example 1-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.5 μm, P content 9 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.8 μm.

REFERENCE EXAMPLE 1-2-5

In reference example 1-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 1-2-6

In reference example 1-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 1-2-7

In reference example 1-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 1-2-8

In reference example 1-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 1-2-9

In reference example 1-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.5 μm.

REFERENCE EXAMPLE 1-2-10

In reference example 1-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 1-2-11

In reference example 1-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 1-2-12

In reference example 1-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.9 μm.

Embodiment 2

The above mentioned embodiment 1, with referring to FIGS. 1-7, concernsto the build-up multi printed board. Whereas, embodiment 2 concerns to alaminated multilayer printed board.

FIG. 9 shows the cross section of a printed circuit board 30 inembodiment 2. The multilayer printed circuit board 30 is a semiconductormounting printed board which mounts a IC chip 80. The multilayer printedcircuit board 30 consists of laminated plural circuit boards 31, eachboard 31 has through holes 36, via holes 38 and conductor circuits 34.The conductor circuits 34U are formed on the upper surface of multilayerprinted circuit board 30. The conductor circuits 34D are formed on thelower surface of multilayer printed circuit board 30. Solder resistlayer 70 is formed on the surface side of the upper conductor circuits34U. A part of conductor circuit 34U is exposed through opening portion71 of solder resist layer 70, the exposed portion consists bonding pad42. Also, solder resist layer 70 is formed on the surface side of thelower conductor circuits 34D. A part of conductor circuit 34D is exposedthrough opening portion 71 of solder resist layer 70, the exposedportion consists bonding pad 44. solder layer 46 for connecting tooutside circuit boards is formed on solder pad 44. IC chip 80 is mountedon the upper surface of multilayer printed circuit board 30 via adhesive84. Terminals 86 of IC chip 80 and bonding pads 44 of the multilayerprinted circuit board are bonding connected via wires 82.

Next, the solder pads will be explained with referring to FIG. 14. FIG.14(B) enlarged shows circle B part of multilayer printed circuit board30 in FIG. 9. Nickel plated layer 72 is formed on conductor circuit 34D.The conductor circuit 34D is connected to solder layer 46 via Ni—Snalloy layer 75 on nickel plated layer 72. In embodiment 2, bycontrolling the average thickness of Cu—Ni—Sn alloy layer 75, theoccurrence of the breakage in the interface between the nickel platedlayers 72 and the solder layer 46 can be reduced. Thereby, the strengthand adhesion of solder layer 46 can be improved.

Hereafter, a method for manufacturing the multilayer printed wiringboard 30 described above will next be described with reference to FIGS.10 to 13.

The printed circuit boards 31 having circuit patterns 34 and via holes38 is prepared (FIG. 10(A)). The printed circuit boards 31 are bondedwith adhesive 33 (FIG. 10(B)). The multilayer printed circuit boardsconsisting of the laminated printed circuit boards is drilled to formthrough holes 36 (FIG. 10(C)). Thereafter, the solder resist layer 70having opening portions 71 is formed (FIG. 11(A)).

As shown in FIG. 11(A), conductor circuits 34U are formed on the upperside of the multilayer printed wiring board 30, a part of the conductorcircuits 34U is exposed via the opening portions 71 of the solder resistlayer 70. While, conductor circuits 34D are formed on the lower side ofthe multilayer board. A part of the conductor circuits 34D is exposedvia the opening portions 71 of the solder resist layer 70. It isdesirable to form the roughened surfaces on the conductor circuits 34Uand the conductor circuits 34D so as to tightly bond with the solderresist layer 70.

-   (1) Next, nickel plated layers are formed on the solder pads of the    substrate.

[Nickel Plating Aqueous Solution]

nickel chloride 2.3 × 10⁻¹ mol/l sodium hypophosphite 1.8 to 4.0 × 10⁻¹mol/l sodium citrate 1.6 × 10⁻¹ mol/l pH of 4.5 temperature of 40 to 60°C.

The substrate is immersed in the electroless nickel plating solution for5 to 40 minutes, thereby forming nickel plated layers 72 in the openingportions 71 (FIG. 11(B)).

In Embodiment 2, nickel plated layers 72 are adjusted so as to have athickness of 0.03 to 12 μm, to include 0.4 to 17 wt % of P. Thethickness and the P content of the nickel plated layers are adjusted inconsidering the value of a plating tub and plating solution circulation.Thereby, in the case where the roughened surfaces have been formed onthe conductor circuits 34U and the conductor circuits 34D, an unevenpart of the roughened surfaces can be entirely covered, flattening thesurface of the nickel plated layers 72.

-   (2) Thereafter, palladium layers are formed on the solder pads of    the substrate on which the nickel plated layers have been formed.

[Palladium Plating Aqueous Solution]

palladium chloride 1.0 × 10⁻² mol/l ethylenediamine 8.0 × 10⁻² mol/lsodium hypophosphite 4.0 to 6.0 × 10⁻² mol/l thiodiglycolic acid 30 mg/lpH of 8 temperature of 50 to 60° C.

The substrate is immersed in the electroless palladium plating solutionfor 3 to 10 minutes, thereby forming palladium plated layers 73 having athickness of 0.08 μm on the nickel plated layers 72 (FIG. 12(A)). InEmbodiment 2, palladium plated layers 73 are adjusted so as to have athickness of 0.008 to 2.0 μm, to include 1 to 8 wt % of P. The thicknessand the P content of the palladium plated layers are adjusted inconsidering the value of a plating tub and plating solution circulation.Thereby, the bonding pads 42 are formed on the upper side conductorcircuits 34U, and the solder pads 44 are formed on the lower sideconductor circuits 34D. Here, gold layers can be formed on the palladiumplated layers as oxidation resistance layers. In Embodiment 2, palladiumplated layers 73 can be adjusted so as to have a thickness of 0.01 to1.0 μm, to include 2 to 7 wt % of P.

-   (3) Solder paste 76 α is printed on solder pads 44 in each opening    71 of the solder resist layer 70 (FIG. 12(B)). The solder pad 44 in    FIG. 12(B) is enlarged shown in FIG. 14(A). The solder pad 44    consists of the multi-layers, that is, the two layers comprises    nickel plated layers 72—palladium plated layers 73 which have been    formed in turn on the conductor circuit 34D.-   (4) Thereafter, solder layer 46 are formed by conducting reflow at    250° C. in nitrogenous atmosphere (FIG. 13(A)). During the reflow,    palladium plated layers 73 and gold plated layers 64 almost diffuse    into solder layer 46, Cu—Ni—Sn alloy layer 75, consisted of the    nickel layers and composition metal of the solder, is formed in the    interface between nickel plated layers 72 and solder layer 46 as    shown in FIG. 9 and FIG. 14(B). Here, in Embodiment 2, the palladium    plated layers 73 is adjusted so as to have a thickness of 0.01 to    1.0 μm and the P content is adjusted to 2 to 7 wt %, thereby    controlling the average thickness of Cu—Ni—Sn alloy layer 75. It    reduces the occurrence of the breakage in the interface between the    nickel plated layers 72 and the solder layer 46.-   (5) IC chip 80 is mounted on the upper side of the finished    multilayer printed wiring board 30 with adhesive 84 (FIG. 13(B)).    Thereafter, bonding wires 82 are bonded between terminals 86 of IC    chip 80 and bonding pads 42 of multilayer printed wiring board 30    (Refer to FIG. 9). While, outer connecting terminals (in this case,    BGA:BALL GRID ARRAY) are placed on the solder layers. PGA (PIN GRID    ARRAY) can be placed as the outer connecting terminals. Also,    capacitances or the like may be mounted on the solder layers.

Embodiment 2-1-1

In embodiment 2-1-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 5 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form.In embodiment 2-1-1, as shown in the electron microscope picture in theleft side of FIG. 18, the Ni—Cu—Sn alloy layer is typically aboard-shaped form, that is, formed in parallel with the Ni layer as sameas above mentioned embodiment 1-1-1.

Embodiment 2-1-2

In embodiment 2-1-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-3

In embodiment 2-1-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-4

In embodiment 2-1-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-5

In embodiment 2-1-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-6

In embodiment 2-1-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 0.01 μm, P content 7 wt %. Therefore, the composition ofthe Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-7

In embodiment 2-1-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.05 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-8

In embodiment 2-1-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.05 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 3 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.8 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-9

In embodiment 2-1-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-10

In embodiment 2-1-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.6 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-11

In embodiment 2-1-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-12

In embodiment 2-1-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.6 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-13

In embodiment 2-1-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-14

In embodiment 2-1-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-15

In embodiment 2-1-15, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 5 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-16

In embodiment 2-1-16, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-17

In embodiment 2-1-17, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.05 μm, P content 10 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.8 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-18

In embodiment 2-1-18, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 10 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 5 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.8 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-19

In embodiment 2-1-19, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.05 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 2.0 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-20

In embodiment 2-1-20, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 1.9 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-1-21

In embodiment 2-1-21, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 8 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, thethickness becomes 2.0 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 2-1-22

In embodiment 2-1-22, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 10 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thicknessbecomes 2.1 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 2-2-1

In embodiment 2-1-1, the Cu/Ag/Sn solder which does not include lead isused as the solder consisting of the solder layer. Whereas, inembodiment 2-2-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 0.5μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-2

In embodiment 2-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-3

In embodiment 2-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-4

In embodiment 2-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-5

In embodiment 2-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-6

In embodiment 2-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-7

In embodiment 2-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-8

In embodiment 2-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 3 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-9

In embodiment 2-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-10

In embodiment 2-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-11

In embodiment 2-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-12

In embodiment 2-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-13

In embodiment 2-2-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-14

In embodiment 2-2-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 2-2-15

In embodiment 2-2-15, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 8 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-16

In embodiment 2-2-16, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 8 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-17

In embodiment 2-2-17, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 10 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-18

In embodiment 2-2-18, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 10 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-19

In embodiment 2-2-19, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 15 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.9 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-20

In embodiment 2-2-20, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 m, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-21

In embodiment 2-2-21, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 8 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.1 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-2-22

In embodiment 2-2-22, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.2 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 2-3-1

In embodiments 2-3-1 to 2-3-14, the alloy of Cu:0.5 wt %, Ag:3.5 wt %,Sn:95 wt % is used as a solder consisting of the solder layer as same asembodiments 2-1-1 to 2-1-14. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt % as same as embodiment 2-1-1. On the other hand, Pdlayer is formed as thickness 0.009 μm, P content 8 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=42:45:13, thethickness becomes 2.5 μm. In embodiment 2-3-1, the Cu—Ni—Sn alloy layeris typically a pillar-shaped form, that is, pillar-shaped alloy crystalvertically formed along with the Ni layer as same as embodiment 1-3-1.

Embodiment 2-3-2

In embodiment 2-3-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt % as same as embodiment 2-3-1. On theother hand, Pd layer is formed as thickness 0.008 μm, P content 7 wt %.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Ni—Sn alloy layeris typically a pillar-shaped form.

Embodiment 2-3-3

In embodiment 2-3-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt % as same as embodiment 2-3-1. On theother hand, Pd layer is formed as thickness 0.009 μm, P content 1 wt %.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Ni—Sn alloy layeris typically a pillar-shaped form.

Embodiment 2-3-4

In embodiment 2-3-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt % as same as embodiment 2-3-1. On theother hand, Pd layer is formed as thickness 2.0 μm, P content 2 wt %.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloy layer istypically a grain-shaped and formed at an interface of the Ni layer.

Embodiment 2-3-5

In embodiment 2-3-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 5 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-6

In embodiment 2-3-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 2.0 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.5μm. The Ni—Sn alloy layer is typically a grain-shaped and formed at aninterface of the Ni layer.

Embodiment 2-3-7

In embodiment 2-3-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.03 μm, P content 3 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, thethickness becomes 1.1 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 2-3-8

In embodiment 2-3-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.03 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-9

In embodiment 2-3-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.03 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-10

In embodiment 2-3-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 10 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.4 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-11

In embodiment 2-3-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 10 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes1.5 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-12

In embodiment 2-3-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes2.4 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-13

In embodiment 2-3-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes2.5 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-3-14

In embodiment 2-3-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=66:29:5, the thickness becomes2.4 μm. The Ni—Sn alloy layer is typically a grain-shaped and formed atan interface of the Ni layer.

Embodiment 2-4-1

In embodiments 2-4-1 to 2-4-14, an alloy of Sn:Pb=63:37 (wt %) is usedas a solder consisting of the solder layer as same as embodiments 2-2-1to 2-2-14. Ni layer is formed as thickness 5 μm, P content 1.2 wt % assame as embodiments 2-2-1. On the other hand, Pd layer is formed asthickness 0.009 μm, P content 8 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.5 μm. TheNi—Sn alloy layer is typically a pillar-shaped form.

Embodiment 2-4-2

In embodiment 2-4-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt % as same as embodiments 2-4-1. On the other hand, Pdlayer is formed as thickness 0.008 μm, P content 7 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 2.5 μm. The Ni—Sn alloy layer is typically a pillar-shaped form.

Embodiment 2-4-3

In embodiment 2-4-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt % as same as embodiments 2-4-1. On the other hand, Pdlayer is formed as thickness 0.009 μm, P content 1 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 2.5 μm. The Ni—Sn alloy layer is typically a pillar-shaped form.

Embodiment 2-4-4

In embodiment 2-4-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt % as same as embodiments 2-4-1. On the other hand, Pdlayer is formed as thickness 2.0 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 1.3 μm. The Ni—Sn alloy layer is typically a grain-shaped andformed at an interface of the Ni layer.

Embodiment 2-4-5

In embodiment 2-4-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 5 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-6

In embodiment 2-4-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 9 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-7

In embodiment 2-4-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.03 μm,P content 0.4 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 3 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.1 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-8

In embodiment 2-4-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.03 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-9

In embodiment 2-4-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.03 μm,P content 16 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-10

In embodiment 2-4-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness 0.2μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-11

In embodiment 2-4-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 16 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-12

In embodiment 2-4-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 12 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-4-13

In embodiment 2-4-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 12 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 2 wt %. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Ni=67:33, the thickness becomes 2.5 μm. The Ni—Sn alloy layeris typically a grain-shaped and formed at an interface of the Ni layer.

Embodiment 2-4-14

In embodiment 2-4-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 12 μm, Pcontent 17 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 2-5-1

In embodiment 2-5-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 0 wt %. When the solder is conducted reflow, fluxcontaining copper is used. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Snalloy layer is typically a grain-shaped form.

Embodiment 2-5-2

In embodiment 2-5-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.07 μm, P content 5 wt %. When the solder is conducted reflow, fluxcontaining copper is used. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Snalloy layer is typically a board-shaped form.

REFERENCE EXAMPLE 2-1-1

In reference examples 2-1-1 to 2-1-12 and reference examples 2-2-1 to2-2-12, a buildup-multi-layer-circuit-board is formed and a solder layeris formed, as same as the above embodiment 2 explained with referring toFIGS. 9-14.

In reference example 2-1-1, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 0 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=38:20:42, the thicknessbecomes 0.8 μm. In reference example 2-1-1, as shown in the electronmicroscope picture in the right side of FIG. 18, the Ni—Cu—Sn alloylayer is typically a pillar-shaped form, that is, pillar-shaped alloycrystal vertically formed along with the Ni layer.

REFERENCE EXAMPLE 2-1-2

In reference example 2-1-2, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 5 μm, P content 4 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 0.8 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, thethickness becomes 0.9 μm.

REFERENCE EXAMPLE 2-1-3

In reference example 2-1-3, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 5 μm, P content 4 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 9 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, the thicknessbecomes 2.7 μm.

REFERENCE EXAMPLE 2-1-4

In reference example 2-1-4, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 5 μm, P content 4 wt %. On the other hand, Pd layer isformed as thickness 1.5 μm, P content 9 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, the thicknessbecomes 2.9 μm.

REFERENCE EXAMPLE 2-1-5

In reference example 2-1-5, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 0 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=38:20:42, the thicknessbecomes 0.8 μm.

REFERENCE EXAMPLE 2-1-6

In reference example 2-1-6, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 2 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 2-1-7

In reference example 2-1-7, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.03 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 9 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 2-1-8

In reference example 2-1-8, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.03 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1.5 μm, P content 9 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, the thicknessbecomes 0.9 μm.

REFERENCE EXAMPLE 2-1-9

In reference example 2-1-9, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97 wt% is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 0 wt %. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, the thicknessbecomes 2.5 μm.

REFERENCE EXAMPLE 2-1-10

In reference example 2-1-10, an alloy of Cu:0.2 wt %, Ag:1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 2 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.6 μm.

REFERENCE EXAMPLE 2-1-11

In reference example 2-1-11, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 9 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.7 μm.

REFERENCE EXAMPLE 2-1-12

In reference example 2-1-12, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=39:26:49, thethickness becomes 2.9 μm.

REFERENCE EXAMPLE 2-2-1

In reference examples 2-1-1 to 2-1-12, the Cu/Ag/Sn solder which doesnot include lead is used as the solder consisting of the solder layer.Whereas, in reference examples 2-2-1 to 2-2-12, an alloy of Sn:Pb=63:37(wt %) is used as a solder consisting of the solder layer. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 0.8 μm.

REFERENCE EXAMPLE 2-2-2

In reference example 2-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 0.8 wt %. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 2-2-3

In reference example 2-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 9 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 2-2-4

In reference example 2-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.5 μm, P content 9 wt %. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Ni=67:33, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 2-2-5

In reference example 2-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 2-2-6

In reference example 2-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 1.1 μm.

REFERENCE EXAMPLE 2-2-7

In reference example 2-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 7 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 2-2-8

In reference example 2-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 7 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 2-2-9

In reference example 2-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.5 μm.

REFERENCE EXAMPLE 2-2-10

In reference example 2-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 2-2-11

In reference example 2-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 7 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 2-2-12

In reference example 2-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 7 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Therefore, the composition of theNi—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.9 μm.

Embodiment 3

The configuration of a multilayer printed wiring board 10 according toEmbodiment 3 of the present invention will first be described withreference to FIG. 20 showing the cross section thereof. Theconfiguration of Embodiment 3 is as same as Embodiment 1. The multilayerprinted wiring board 10 has a conductor circuit 34 formed on the frontsurface of a core substrate 30. The front and rear surfaces of the coresubstrate 30 are connected to each other via through holes 36. Inaddition, an interlayer resin insulating layer 50 on which via holes 60and conductor circuits 58 are formed and an interlayer resin insulatinglayer 150 on which via holes 160 and conductor circuits 158 are formedare provided on the both surfaces of the core substrate 30. Solderresist layers 70 are formed on upper layers of the via holes 160 and theconductor circuits 158, and solder pads 77U and 77D are formed on theconductor circuits 158 through the opening portions 71 of the solderresist layers 70, respectively. Bumps 76U and 76D are formed on thesolder pads 77U and 77D.

Next, the solder pads 76U will be described with referring to FIG.24(B). FIG. 24(B) enlarged shows circle A part of multilayer printedcircuit board 10 in FIG. 20. Nickel plated layer 72 is formed onconductor circuit 158. The conductor circuit 158 is connected to solderlayer (bump) 46 via Ni—Sn alloy layer 75 on nickel plated layer 72. Inembodiment 3, by controlling the average thickness of Ni—Sn alloy layer75, the occurrence of the breakage in the interface between the nickelplated layers 72 and the solder layer 46 can be reduced. Thereby, thestrength, and adhesion of solder layer 46 can be improved.

Hereafter, a method for manufacturing the multilayer printed wiringboard 10 in Embodiment 3 will next be described with reference to FIGS.22 to 24.

Since the steps (1) to (17) in Embodiment 1 have been described withreferring to FIGS. 2 to 5 are almost the same as the steps in Embodiment3, the explanation will start from step (18) forming the nickel platedlayers.

-   (18) Next, nickel plated layers are formed on the solder pads of the    substrate having the solder resist layers 70 shown in FIG. 22(A).

[Nickel Plating Aqueous Solution]

nickel chloride 2.3 × 10⁻¹ mol/l sodium hypophosphite 1.8 to 4.0 × 10⁻¹mol/l sodium citrate 1.6 × 10⁻¹ mol/l pH of 4.5 temperature of 40 to 60°C.

The substrate is immersed in the electroless nickel plating solution for5 to 40 minutes, thereby forming nickel plated layers 72 in the openingportions 71 (FIG. 22(B)). In the Embodiment 3, nickel plated layers 72are adjusted so as to have a thickness of 0.03 to 10 μm, to include 0.4to 17 wt % of P. The thickness and the P content of the nickel platedlayers are adjusted in considering the value of a plating tub andplating solution circulation.

-   (19) Thereafter, palladium layers are formed on the solder pads on    which the nickel plated layers have been formed in step (18) of the    substrate.

[Palladium Plating Aqueous Solution]

palladium chloride 1.0 × 10⁻² mol/l ethylenediamine 8.0 × 10⁻² mol/lsodium hypophosphite 4.0 to 6.0 × 10⁻² mol/l thiodiglycolic acid 30 mg/lpH of 8 temperature of 50 to 60° C.

The substrate is immersed in the electroless palladium plating solutionfor 3 to 10 minutes, thereby forming palladium plated layers 73 having athickness of 0.08 μm on the nickel plated layers 72 (FIG. 22(C)). In theEmbodiment 3, palladium plated layers 73 are adjusted so as to have athickness of 0.008 to 2.0 μm, to include 1 to 8 wt % of P. The thicknessand the P content of the palladium plated layers are adjusted inconsidering the value of a plating tub and plating solution circulation.

-   (20) Thereafter, gold layers are formed on the surface layer as    oxidation resistance layers.

[Gold Plating Aqueous Solution]

potassium gold cyanide 7.6 × 10⁻³ mol/l ammonium chloride 1.9 × 10⁻¹mol/l sodium citrate 1.2 × 10⁻¹ mol/l sodium hypophosphite 1.7 × 10⁻¹mol/l

The substrate is immersed in the electroless gold plating solution at80° C. for 5 to 20 minutes, thereby forming gold plated layers 74 havinga thickness of 0.01 to 2 μm on the palladium plated layers 73 (FIG.23(A)). Thereby, bonding pads 42 are formed on the upper side of theconductor circuits 34U, and solder pads 44 are formed on the lower sideof the conductor circuits 34D.

-   (21) Solder paste 76 α is printed on solder pads 77U, 77D in each    opening 71 of the solder resist layer 70 (FIG. 23(B)). The solder    pad 77U in the circle A in FIG. 23(B) is enlarged shown in FIG.    24(A). The solder pad 77U consists of the multi-layers, that is, the    three layers comprises nickel plated layers 72—palladium plated    layers 73—gold plated layers 74 which have been formed in turn on    the conductor circuit 158.-   (22) Thereafter, solder bumps 76U, 76D are formed by conducting    reflow at 250° C. in nitrogenous atmosphere (FIG. 20). The solder    pad 77U in the circle A in FIG. 20 is enlarged shown in FIG. 24(B).    During the reflow, palladium plated layers 73 and gold plated layers    74 almost diffuse into solder bumps 76U, 76D, Cu—Ni—Sn alloy layer    75 or Ni layer alloy layer is formed in the interface between nickel    plated layers 72 and solder bumps 76U, 76D as shown in FIG. 20 and    FIG. 24(B).

Here, the nickel plated layers 72 is adjusted so as to have thethickness of 0.05 to 10 μm and the P content is adjusted to 0.4 to 17 wt% which is lower or higher than thereof the palladium layers. And thepalladium plated layers 73 is adjusted so as to have thickness of 0.01to 1.0 μm and the P content is adjusted to 2 to 7 wt %. Thereby, theaverage thickness of Cu—Ni—Sn alloy layer 75 is controlled between 1.0and 2.5 μm.

Embodiment 3-1-1

In embodiment 3-1-1, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 5 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. Electronmicroscope pictures of Ni layer, Cu—Ni—Sn alloy and solder in embodiment3-1-1 are the same as embodiment 1-1-1 described with referring to FIGS.15-18. The electron microscope picture (×20 k) in the left side of FIG.15 corresponds to embodiment 3-1-1. The electron microscope pictures(×100 k) in the left sides of FIGS. 16, 17 are a more enlarged scale.The right sides of electron microscope pictures in FIGS. 15, 16, 17 showPd layers which do not contain P in reference example 3-1-1. The lowerside is the Ni layer and the upper side is the solder and the interfacebetween the Ni layer and the solder is the Cu—Ni—Sn alloy. As shown inthe electron microscope picture in the left side of FIG. 15, inembodiment 3-1-1, the Cu—Ni—Sn alloy is consecutively formed on thesurface of Ni layer, that is, is slightly Ups and downs. As shown in theelectron microscope pictures in the left sides of FIGS. 16, 17 usingenlarged scale, Ag particles uniformly exist on the surface of theCu—Ni—Sn alloy through skin layer of Sn. In embodiment 3-1-1, as shownin the permeation type electron microscope picture in the right side ofFIG. 18, the Ni—Cu—Sn alloy layer is typically aboard-shaped form, thatis, formed in parallel with the Ni layer.

Embodiment 3-1-2

In embodiment 3-1-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-3

In embodiment 3-1-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Au layer is formed asthickness 1.00 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-4

In embodiment 3-1-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 2 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-5

In embodiment 3-1-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 7 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-6

In embodiment 3-1-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 0.01 μm, P content 7 wt %. Au layer is formed as thickness0.01 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 3-1-7

In embodiment 3-1-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.02 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-8

In embodiment 3-1-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 3 wt %. Au layer is formed asthickness 0.01 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-9

In embodiment 3-1-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.2 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-10

In embodiment 3-1-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Au layer is formed asthickness 0.4 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-11

In embodiment 3-1-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-12

In embodiment 3-1-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-13

In embodiment 3-1-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-14

In embodiment 3-1-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 7 wt %. Au layer is formed as thickness 0.5μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 3-1-15

In embodiment 3-1-15, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 5 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-16

In embodiment 3-1-16, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.01 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-17

In embodiment 3-1-17, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 10 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-18

In embodiment 3-1-18, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 10 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 5 wt %. Au layer is formed as thickness0.03 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 3-1-19

In embodiment 3-1-19, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 0.05 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.0 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-1-20

In embodiment 3-1-20, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 1 μm, P content 15 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.5μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.9 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 3-1-21

In embodiment 3-1-21, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 8 μm, P content 15 wt %. On the other hand, Pd layer is formedas thickness 0.01 μm, P content 7 wt %. Au layer is formed as thickness1 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 2.0 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 3-1-22

In embodiment 3-1-22, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 2 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.1 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 3-2-1

In embodiment 3-1-1, the Cu/Ag/Sn solder which does not include lead isused as the solder consisting of the solder bump. Whereas, in embodiment3-2-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solder consisting ofthe solder bump. Ni layer is formed as thickness 5 μm, P content 1.2 wt%. On the other hand, Pd layer is formed as thickness 0.5 μm, P content5 wt %. Au layer is formed as thickness 0.03 μm. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 3-2-2

In embodiment 3-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-3

In embodiment 3-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 7 wt %. Au layer is formed as thickness 1 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-4

In embodiment 3-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 2 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-5

In embodiment 3-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 7 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-6

In embodiment 3-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 0.0μm, P content 7 wt %. Au layer is formed as thickness 0.01 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-7

In embodiment 3-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.02 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-8

In embodiment 3-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 3 wt %. Au layer is formed as thickness 0.01 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-9

In embodiment 3-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.2 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-10

In embodiment 3-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Au layer is formed as thickness 0.4 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.6 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-11

In embodiment 3-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Au layer is formed as thickness 0.5 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-12

In embodiment 3-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Au layer is formed as thickness 0.03 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.6 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-13

In embodiment 3-2-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.5 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-14

In embodiment 3-2-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Au layer is formed as thickness 0.5 μm. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 3-2-15

In embodiment 3-2-15, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 8 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 5 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-16

In embodiment 3-2-16, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.3 μm, Pcontent 8 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Au layer is formed as thickness 0.01 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-17

In embodiment 3-2-17, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 10 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-18

In embodiment 3-2-18, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 10 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 5 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-19

In embodiment 3-2-19, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.05 μm,P content 15 wt %. On the other hand, Pd layer is formed as thickness0.0 μm, P content 2 wt %. Au layer is formed as thickness 0.5 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.0 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-20

In embodiment 3-2-20, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 1 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Au layer is formed as thickness 0.5 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.9 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-21

In embodiment 3-2-21, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 8 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Au layer is formed as thickness 1 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 2.0 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-2-22

In embodiment 3-2-22, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 2 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 2.1 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 3-3-1

In embodiment 3-3-1, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump as same as embodiment3-1-1. Ni layer is formed as thickness 5 μm, P content 1.2 wt % as sameas embodiment 3-1-1. On the other hand, Pd layer is formed as thickness0.009 μm, P content 8 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. In embodiment 3-3-1, asshown in the electron microscope picture in right side of FIG. 18, theNi—Cu—Sn alloy layer is typically a pillar-shaped form, that is,pillar-shaped alloy crystal vertically formed along with the Ni layer assame as the above mentioned reference example 3-2-1.

Embodiment 3-3-2

In embodiment 3-3-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.008 μm, P content 7 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Ni—Sn alloylayer is typically a pillar-shaped form.

Embodiment 3-3-3

In embodiment 3-3-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.009 μm, P content 1 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Ni—Sn alloylayer is typically a pillar-shaped form.

Embodiment 3-3-4

In embodiment 3-3-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 2 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-5

In embodiment 3-3-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 5 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-6

In embodiment 3-3-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 2.0 μm, P content 9 wt %. Au layer is formed as thickness0.06 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=66:29:5, the thickness becomes 1.5 μm. The Ni—Sn alloy layer istypically a grain-shaped and formed at an interface of the Ni layer.

Embodiment 3-3-7

In embodiment 3-3-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.03 μm, P content 3 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.1 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-8

In embodiment 3-3-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.03 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-9

In embodiment 3-3-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder bump. Ni layer is formed asthickness 0.03 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-10

In embodiment 3-3-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 2 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-11

In embodiment 3-3-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 10 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.0 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-12

In embodiment 3-3-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 12 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-3-13

In embodiment 3-3-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 12 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 1 μm, P content 2 wt %. Au layer is formed as thickness0.02 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=66:29:5, the thickness becomes 2.5 μm. The Ni—Sn alloy layer istypically a grain-shaped and formed at an interface of the Ni layer.

Embodiment 3-3-14

In embodiment 3-3-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder bump. Ni layer is formed asthickness 12 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 3-4-1

In embodiment 3-4-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.009 μm, P content 8 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 3-4-2

In embodiment 3-4-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.008 μm, P content 7 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 3-4-3

In embodiment 3-4-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.009 μm, P content 1 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 3-4-4

In embodiment 3-4-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 2 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-5

In embodiment 3-4-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 5 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-6

In embodiment 3-4-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 9 wt %. Au layer is formed as thickness 0.06 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-7

In embodiment 3-4-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.03 μm,P content 0.4 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 3 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-8

In embodiment 3-4-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.03 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-9

In embodiment 3-4-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 0.03 μm,P content 16 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-10

In embodiment 3-4-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness 0.2μm, P content 2 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.4 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-11

In embodiment 3-4-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 10 μm, Pcontent 16 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.010 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-12

In embodiment 3-4-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 12 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.4 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-13

In embodiment 3-4-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 12 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 2 wt %. Au layer is formed as thickness 0.02 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 2.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-4-14

In embodiment 3-4-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 12 μm, Pcontent 17 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.4 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 3-5-1

In embodiment 3-5-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 0 wt %. (As shown in the electron microscope picturein FIG. 19, Pd layer partly separates out, and under Ni layer can beseen via porous of the Pd layer as same as embodiment 1-5-1.) Au layeris formed as thickness 0.05 μm. When the solder is conducted reflow,flux containing copper is used. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. TheNi—Sn alloy layer is typically a grain-shaped form.

Embodiment 3-5-2

In embodiment 3-5-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder bump. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.07 μm, P content 5 wt %. (As shown in the electron microscope picturein FIG. 20, Pd layer is uniformly formed as same as embodiment 1-5-2.)Au layer is formed as thickness 0.07 μm. When the solder is conductedreflow, flux containing copper is used. Therefore, the composition ofthe Ni—Sn alloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes1.5 μm. The Ni—Sn alloy layer is typically a board-shaped form shown inthe electron microscope picture the left side in FIG. 18 as same asembodiment 1-1-1.

REFERENCE EXAMPLE 3-1-1

In reference examples 3-1-1 to 3-1-16 and reference examples 3-2-1 to3-2-16, a buildup-multi-layer-circuit-board is formed and a solder bumpis formed, as same as the above embodiment 3 explained with referring toFIGS. 1-8.

In reference example 3-1-1, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=38:20:42, the thickness becomes 0.8 μm. Theelectron microscope pictures of Ni layer, Cu—Ni—Sn alloy and solder inreference example 3-1-1 are same as reference example 1-1-1 withreferring to FIGS. 15-18. As shown in the electron microscope picture inthe right side of FIG. 15, in reference example 3-1-1, the Cu—Ni—Snalloy is un-consecutively formed on the surface of Ni layer, that is, isUps and downs. As shown in the electron microscope pictures in the rightside of FIGS. 16, 17 using enlarged scale, Ag particles un-uniformlydotted exist on the surface of the Cu—Ni—Sn alloy through skin layer ofSn. In reference example 3-1-1, as shown in the electron microscopepicture in the right side of FIG. 18, the Ni—Cu—Sn alloy layer istypically a pillar-shaped form, that is, pillar-shaped alloy crystalvertically formed along with the Ni layer.

REFERENCE EXAMPLE 3-1-2

In reference example 3-1-2, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump as same asreference example 3-1-1. Ni layer is formed as thickness 5 μm, P content4 wt %. On the other hand, Pd layer is formed as thickness 1.0 μm, Pcontent 0.8 wt %. Au layer is formed as thickness 0.03 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Cu:Ni=40:25:35, thethickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-1-3

In reference example 3-1-3, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.0 μm, P content 9 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 3-1-4

In reference example 3-1-4, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.5 μm, P content 9 wt %. Au layer is formed asthickness 0.02 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 3-1-5

In reference example 3-1-5, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=38:20:42, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 3-1-6

In reference example 3-1-6, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1.0 μm, P content 2 wt %. Au layer isformed as thickness 0.05 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=40:25:35, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-1-7

In reference example 3-1-7, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1.0 μm, P content 9 wt %. Au layer isformed as thickness 0.02 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=40:25:35, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-1-8

In reference example 3-1-8, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Au layer isformed as thickness 0.05 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=40:25:35, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-1-9

In reference example 3-1-9, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.5 μm.

REFERENCE EXAMPLE 3-1-10

In reference example 3-1-10, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 2 wt %. Au layer is formedas thickness 0.02 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 3-1-11

In reference example 3-1-11, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 17 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 9 wt %. Au layer is formedas thickness 0.03 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 3-1-12

In reference example 3-1-12, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 17 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Au layer isformed as thickness 0.05 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 3-1-13

In reference example 3-1-13, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 2 wt %. Au layer is formedas thickness 0.008 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-1-14

In reference example 3-1-14, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 0.03 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 9 wt %. Au layer is formedas thickness 0.008 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-1-15

In reference example 3-1-15, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 2 wt %. Au layer isformed as thickness 2.1 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 3-1-16

In reference example 3-1-16, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump. Ni layer isformed as thickness 12 μm, P content 17 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Au layer isformed as thickness 2.1 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 3-2-1

In reference examples 3-1-1 to 3-1-16, the Cu/Ag/Sn solder which doesnot include lead is used as the solder consisting of the solder bump.Whereas, in reference examples 3-2-1 to 3-2-16, an alloy of Sn:Pb=63:37(wt %) is used as a solder consisting of the solder bump. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Ni=67:33, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 3-2-2

In reference example 3-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 0.8 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-2-3

In reference example 3-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 9 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 3-2-4

In reference example 3-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.5 μm, P content 9 wt %. Au layer is formed as thickness 0.02 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 3-2-5

In reference example 3-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Au layer is formed as thickness 0.03μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 3-2-6

In reference example 3-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.05μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-2-7

In reference example 3-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Au layer is formed as thickness 0.02μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-2-8

In reference example 3-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Au layer is formed as thickness 0.05μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-2-9

In reference example 3-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Au layer is formed as thickness 0.03μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.5 μm.

REFERENCE EXAMPLE 3-2-10

In reference example 3-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.02μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 3-2-11

In reference example 3-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Au layer is formed as thickness 0.03μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 3-2-12

In reference example 3-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Au layer is formed as thickness 0.05μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 3-2-13

In reference example 3-2-13, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.008μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-2-14

In reference example 3-2-14, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness0.03 μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Au layer is formed as thickness 0.008μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 3-2-15

In reference example 3-2-15, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 2 wt %. Au layer is formed as thickness 2.1μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 3-2-16

In reference example 3-2-16, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder bump. Ni layer is formed as thickness 12μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Au layer is formed as thickness 2.1μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.7 μm.

Embodiment 4

The above mentioned embodiment 3 concerns to the build-up multi printedboard. Whereas, embodiment 4 concerns to a laminated multilayer printedboard as same as embodiment 2.

FIG. 24 shows the cross section of a printed circuit board 30 inembodiment 4. The multilayer printed circuit board 30 is a semiconductormounting printed board which mounts a IC chip 80. The multilayer printedcircuit board 30 consists of laminated plural circuit boards 31, eachboard 31 has through holes 36, via holes 38 and conductor circuits 34.The conductor circuits 34U are formed on the upper surface of multilayerprinted circuit board 30. The conductor circuits 34D are formed on thelower surface of multilayer printed circuit board 30. Solder resistlayer 70 is formed on the surface side of the upper conductor circuits34U. Apart of conductor circuit 34U is exposed through opening portion71 of solder resist layer 70, the exposed portion consists bonding pad42. Also, solder resist layer 70 is formed on the surface side of thelower conductor circuits 34D. A part of conductor circuit 34D is exposedthrough opening portion 71 of solder resist layer 70, the exposedportion consists bonding pad 44. solder layer 46 for connecting tooutside circuit boards is formed on solder pad 44. IC chip 80 is mountedon the upper surface of multilayer printed circuit board 30 via adhesive84. Terminals 86 of IC chip 80 and bonding pads 44 of the multilayerprinted circuit board are bonding connected via wires 82.

Next, the solder pads will be explained with referring to FIG. 29. FIG.29(B) enlarged shows circle B part of multilayer printed circuit board30 in FIG. 25. Nickel plated layer 72 is formed on conductor circuit34D. The conductor circuit 34D is connected to solder layer 46 via Nialloy layer 75 on nickel plated layer 72. In embodiment 4, bycontrolling the average thickness of Ni alloy layer 75, to reduce theoccurrence of the breakage in the interface between the nickel platedlayers 72 and the solder layer 46. Thereby, the strength and adhesion ofsolder layer 46 can be improved.

Hereafter, a method for manufacturing the multilayer printed wiringboard 30 in Embodiment 4 will next be described with reference to FIGS.26 to 29.

Since the treatment steps forming solder resist layer 70 having openingportions 71 in Embodiment 4 have been described with referring to FIGS.10 to 11(A) are almost the same as the steps in Embodiment 4, theexplanation thereof will be omitted.

-   (1) Next, nickel plated layers are formed on the solder pads 34U,    34D in opening portion 71 of solder resist layer 70 shown in FIG.    26(A).

[Nickel Plating Aqueous Solution]

nickel chloride 2.3 × 10⁻¹ mol/l sodium hypophosphite 1.8 to 4.0 × 10⁻¹mol/l sodium citrate 1.6 × 10⁻¹ mol/l pH of 4.5 temperature of 40 to 60°C.

The substrate is immersed in the electroless nickel plating solution for5 to 40 minutes, thereby forming nickel plated layers 72 in the openingportions 71 (FIG. 26(B)).

In Embodiment 4, nickel plated layers 72 are adjusted so as to have athickness of 0.03 to 10 μm, to include 0.4 to 17 wt % of P. Thethickness and the P content of the nickel plated layers are adjusted inconsidering the value of a plating tub and plating solution circulation.Thereby, in the case where the roughened surfaces have been formed onthe conductor circuits 34U and the conductor circuits 34D, an unevenpart of the roughened surfaces can be entirely covered, flattening thesurface of the nickel plated layers 72.

-   (2) Thereafter, palladium layers are formed on the solder pads of    the substrate on which the nickel plated layers have been formed.

[Palladium Plating Aqueous Solution]

palladium chloride 1.0 × 10⁻² mol/l ethylenediamine 8.0 × 10⁻² mol/lsodium hypophosphite 4.0 to 6.0 × 10⁻² mol/l thiodiglycolic acid 30 mg/lpH of 8 temperature of 50 to 60° C.

The substrate is immersed in the electroless palladium plating solutionfor 3 to 10 minutes, thereby forming palladium plated layers 73 having athickness of 0.08 μm on the nickel plated layers 72 (FIG. 26(C)). InEmbodiment 4, palladium plated layers 73 are adjusted so as to have athickness of 0.008 to 2.0 μm, to include 1 to 8 wt % of P. The thicknessand the P content of the palladium plated layers are adjusted inconsidering the value of a plating tub and plating solution circulation.Thereby, the bonding pads 42 are formed on the upper side conductorcircuits 34U, and the solder pads 44 are formed on the lower sideconductor circuits 34D. In Embodiment 4, palladium plated layers 73 canbe adjusted so as to have a thickness of 0.01 to 1.0 μm, to include 2 to7 wt % of P.

-   (3) Thereafter, gold layers are formed on the surface layer as    oxidation resistance layers.

[Gold Plating Aqueous Solution]

potassium gold cyanide 7.6 × 10⁻³ mol/l ammonium chloride 1.9 × 10⁻¹mol/l sodium citrate 1.2 × 10⁻¹ mol/l sodium hypophosphite 1.7 × 10⁻¹mol/l

The substrate is immersed in the electroless gold plating solution at80° C. for 5 to 20 minutes, thereby forming gold plated layers 74 havinga thickness of 0.01 to 2 μm on the palladium plated layers 73 (FIG.27(A)). Thereby, bonding pads 42 are formed on the upper side of theconductor circuits 34U, and solder pads 44 are formed on the lower sideof the conductor circuits 34D.

-   (4) Solder paste 76 a is printed on solder pads 44 in each opening    71 of the solder resist layer 70 (FIG. 27(B)). The solder pad 44 in    FIG. 27(B) is enlarged shown in FIG. 29(A). The solder pad 44    consists of the multi-layers, that is, the three layers comprises    nickel plated layers 72—palladium plated layers 73—gold plated    layers 74 which have been formed in turn on the conductor circuit    34D.-   (5) Thereafter, solder layer 46 are formed by conducting reflow at    250° C. in nitrogenous atmosphere (FIG. 28(A)). During the reflow,    palladium plated layers 73 and gold plated layers 64 almost diffuse    into solder layer 46, Cu—Ni—Sn alloy layer 75, consisted of the    nickel layers and composition metal of the solder, is formed the    interface between nickel plated layers 72 and solder layer 46 as    shown in FIG. 25 and FIG. 29(B). Here, in Embodiment 4, the    palladium plated layers 73 is adjusted so as to have a thickness of    0.01 to 1.0 μm and the P content is adjusted to 2 to 7 wt %, thereby    controlling the average thickness of Cu—Ni—Sn alloy layer 75. It    reduces the occurrence the breakage in the interface between the    nickel plated layers 72 and the solder layer 46.-   (6) IC chip 80 is mounted on the upper side of the finished    multilayer printed wiring board 30 with adhesive 84 (FIG. 28(B)).    Thereafter, bonding wires 82 are bonded between terminals 86 of IC    chip 80 and bonding pads 42 of multilayer printed wiring board 30    (Refer to FIG. 25). While, outer connecting terminals (in this case,    BGA) are placed on the solder layers. PGA can be placed as the outer    connecting terminals. Also, capacitances or the like may be mounted    on the solder layers.

Embodiment 4-1-1

In embodiment 4-1-1, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.5 μm, P content 5 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. In embodiment4-1-1, as shown in the electron microscope picture in the left side ofFIG. 18, the Ni—Cu—Sn alloy layer is typically a board-shaped form, thatis, formed in parallel with the Ni layer as same as above mentionedembodiment 1-1-1.

Embodiment 4-1-2

In embodiment 4-1-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-3

In embodiment 4-1-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 7 wt %. Au layer is formed asthickness 1.0 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-4

In embodiment 4-1-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 2 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-5

In embodiment 4-1-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1.0 μm, P content 7 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-6

In embodiment 4-1-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 0.01 μm, P content 7 wt %. Au layer is formed as thickness0.01 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloy layeris typically a board-shaped form.

Embodiment 4-1-7

In embodiment 4-1-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.05 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.02 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-8

In embodiment 4-1-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.05 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.0 μm, P content 3 wt %. Au layer is formed asthickness 0.01 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-9

In embodiment 4-1-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.2 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-10

In embodiment 4-1-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Au layer is formed asthickness 0.4 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-11

In embodiment 4-1-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-12

In embodiment 4-1-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.6 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-13

In embodiment 4-1-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-14

In embodiment 4-1-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-15

In embodiment 4-1-15, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 5 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-16

In embodiment 4-1-16, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.3 μm, P content 8 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.01 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.7 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-17

In embodiment 4-1-17, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.05 μm, P content 10 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-18

In embodiment 4-1-18, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μam, P content 10 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 5 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.8 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-19

In embodiment 4-1-19, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 0.05 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 2 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.0 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-20

In embodiment 4-1-20, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 1 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Au layer is formed asthickness 0.5 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 1.9 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-21

In embodiment 4-1-21, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 8 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 0.01 μm, P content 7 wt %. Au layer is formed asthickness 1 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.0 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-1-22

In embodiment 4-1-22, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 10 μm, P content 15 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 2 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.1 μm. The Ni—Sn alloylayer is typically a board-shaped form.

Embodiment 4-2-1

In embodiment 4-1-1, the Cu/Ag/Sn solder which does not include lead isused as the solder consisting of the solder layer. Whereas, inembodiment 4-2-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 0.5μm, P content 5 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-2

In embodiment 4-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-3

In embodiment 4-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 7 wt %. Au layer is formed as thickness 5 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-4

In embodiment 4-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 1.0μm, P content 2 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-5

In embodiment 4-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 1.0λm, P content 7 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-6

In embodiment 4-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 0.0μm, P content 7 wt %. Au layer is formed as thickness 0.01 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-7

In embodiment 4-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.02 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-8

In embodiment 4-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 3 wt %. Au layer is formed as thickness 0.01 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-9

In embodiment 4-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.2 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-10

In embodiment 4-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Au layer is formed as thickness 0.4 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.6 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-11

In embodiment 4-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 7 wt %. Au layer is formed as thickness 0.5 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-12

In embodiment 4-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 5 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.6 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-13

In embodiment 4-2-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.5 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-14

In embodiment 4-2-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 7 wt %. Au layer is formed as thickness 0.5 μm. Therefore, thecomposition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thicknessbecomes 1.7 μm. The Ni—Sn alloy layer is typically a board-shaped form.

Embodiment 4-2-15

In embodiment 4-2-15, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 8 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 5 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-16

In embodiment 4-2-16, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.3 μm,P content 8 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.01 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.7 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-17

In embodiment 4-2-17, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 10 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-18

In embodiment 4-2-18, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 10 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 5 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.8 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-19

In embodiment 4-2-19, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.05 μm,P content 15 wt %. On the other hand, Pd layer is formed as thickness0.01 μm, P content 2 wt %. Au layer is formed as thickness 0.5 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.0 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-20

In embodiment 4-2-20, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 1 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Au layer is formed as thickness 0.5 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 1.9 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-21

In embodiment 4-2-21, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 8 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 0.01μm, P content 7 wt %. Au layer is formed as thickness 1 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 2.0 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-2-22

In embodiment 4-2-22, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 15 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 2 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 2.1 μm. The Ni—Sn alloy layer is typically aboard-shaped form.

Embodiment 4-3-1

In embodiments 4-3-1 to 4-3-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %,Sn:95 wt % is used as a solder consisting of the solder layer as same asembodiments 4-1-1 to 4-1-14. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.009 μm, P content 8 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Cu—Ni—Sn alloylayer is typically a pillar-shaped form, that is, pillar-shaped alloycrystal vertically formed along with the Ni layer.

Embodiment 4-3-2

In embodiment 4-3-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.008 μm, P content 7 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Ni—Sn alloylayer is typically a pillar-shaped form.

Embodiment 4-3-3

In embodiment 4-3-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 0.009 μm, P content 1 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:45:13, the thickness becomes 2.5 μm. The Ni—Sn alloylayer is typically a pillar-shaped form.

Embodiment 4-3-4

In embodiment 4-3-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 5 μm, P content 1.2 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 2 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-5

In embodiment 4-3-5, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness loam, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 2.0 μm, P content 5 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-6

In embodiment 4-3-6, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 10 μm, P content 5 wt %. On the other hand, Pd layer is formedas thickness 2.0 μm, P content 9 wt %. Au layer is formed as thickness0.06 μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=66:29:5, the thickness becomes 1.5 μm. The Ni—Sn alloy layer istypically a grain-shaped and formed at an interface of the Ni layer.

Embodiment 4-3-7

In embodiment 4-3-7, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.03 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.03 μm, P content 3 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.1 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-8

In embodiment 4-3-8, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.03 μm, P content 0.5 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-9

In embodiment 4-3-9, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt % isused as a solder consisting of the solder layer. Ni layer is formed asthickness 0.03 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 7 wt %. Au layer is formed asthickness 0.05 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.3 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-10

In embodiment 4-3-10, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 10 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 0.2 μm, P content 2 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-11

In embodiment 4-3-11, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 10 μm, P content 16 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.01 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 1.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-12

In embodiment 4-3-12, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 0.4 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-13

In embodiment 4-3-13, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 5 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 2 wt %. Au layer is formed asthickness 0.02 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 2.5 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-3-14

In embodiment 4-3-14, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95 wt %is used as a solder consisting of the solder layer. Ni layer is formedas thickness 12 μm, P content 17 wt %. On the other hand, Pd layer isformed as thickness 1 μm, P content 7 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=66:29:5, the thickness becomes 2.4 μm. The Ni—Sn alloylayer is typically a grain-shaped and formed at an interface of the Nilayer.

Embodiment 4-4-1

In embodiments 4-4-1 to 4-4-14, an alloy of Sn:Pb=63:37 (wt %) is usedas a solder consisting of the solder layer as same as embodiments 4-2-1to 4-2-14. Ni layer is formed as thickness 5 μm, P content 1.2 wt %. Onthe other hand, Pd layer is formed as thickness 0.009 μm, P content 8 wt%. Au layer is formed as thickness 0.03 μm. Therefore, the compositionof the Ni—Sn alloy layer becomes Sn:Ni=67:33, the thickness becomes 2.5μm. The Ni—Sn alloy layer is typically a pillar-shaped form.

Embodiment 4-4-2

In embodiment 4-4-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.008 μm, P content 7 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 4-4-3

In embodiment 4-4-3, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.009 μm, P content 1 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.5 μm. The Ni—Sn alloy layer is typically apillar-shaped form.

Embodiment 4-4-4

In embodiment 4-4-4, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 2 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-5

In embodiment 4-4-5, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 0.5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 5 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-6

In embodiment 4-4-6, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 2.0μm, P content 9 wt %. Au layer is formed as thickness 0.06 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-7

In embodiment 4-4-7, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.03 μm,P content 0.4 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 3 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.1 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-8

In embodiment 4-4-8, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.03 μm,P content 0.5 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-9

In embodiment 4-4-9, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 0.03 μm,P content 16 wt %. On the other hand, Pd layer is formed as thickness0.2 μm, P content 7 wt %. Au layer is formed as thickness 0.05 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.3 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-10

In embodiment 4-4-10, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness 0.2μm, P content 2 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.4 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-11

In embodiment 4-4-11, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 10 μm, Pcontent 16 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.01 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 1.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-12

In embodiment 4-4-12, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 12 μm, Pcontent 0.4 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 2 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.4 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-13

In embodiment 4-4-13, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 12 μm, Pcontent 5 wt %. On the other hand, Pd layer is formed as thickness 1 μm,P content 2 wt %. Au layer is formed as thickness 0.02 μm. Therefore,the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33, thethickness becomes 2.5 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-4-14

In embodiment 4-4-14, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 12 μm, Pcontent 17 wt %. On the other hand, Pd layer is formed as thickness 1μm, P content 7 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.4 μm. The Ni—Sn alloy layer is typically agrain-shaped and formed at an interface of the Ni layer.

Embodiment 4-5-1

In embodiment 4-5-1, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.03 μm, P content 0 wt %. Au layer is formed as thickness 0.05 μm. Whenthe solder is conducted reflow, flux containing copper is used.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloy layeris typically a grain-shaped form.

Embodiment 4-5-2

In embodiment 4-5-2, an alloy of Sn:Pb=63:37 (wt %) is used as a solderconsisting of the solder layer. Ni layer is formed as thickness 5 μm, Pcontent 1.2 wt %. On the other hand, Pd layer is formed as thickness0.07 μm, P content 5 wt %. Au layer is formed as thickness 0.07 μm. Whenthe solder is conducted reflow, flux containing copper is used.Therefore, the composition of the Ni—Sn alloy layer becomesSn:Cu:Ni=42:37:21, the thickness becomes 1.5 μm. The Ni—Sn alloy layeris typically a board-shaped form.

REFERENCE EXAMPLE 4-1-1

In reference examples 4-1-1 to 4-1-16 and reference examples 4-2-1 to4-2-16, a buildup-multi-layer-circuit-board is formed and a solder layeris formed, as same as the above embodiment 4 explained with referring toFIGS. 25-29.

In reference example 4-1-1, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=42:37:21, the thickness becomes 0.8 μm. Inreference example 4-1-1, as shown in the electron microscope picture inthe right side of FIG. 18, the Ni—Cu—Sn alloy layer is typically apillar-shaped form, that is, pillar-shaped alloy crystal verticallyformed along with the Ni layer.

REFERENCE EXAMPLE 4-1-2

In reference example 4-1-2, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.0 μm, P content 0.8 wt %. Au layer is formed asthickness 0.03 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-1-3

In reference example 4-1-3, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.0 μm, P content 9 wt %. Au layer is formed asthickness 0.04 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 4-1-4

In reference example 4-1-4, an alloy of Cu:0.5 wt %, Ag:3.5 wt %, Sn:95wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 5 μm, P content 4 wt %. On the other hand, Pd layeris formed as thickness 1.5 μm, P content 9 wt %. Au layer is formed asthickness 0.02 μm. Therefore, the composition of the Ni—Sn alloy layerbecomes Sn:Cu:Ni=42:37:21, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 4-1-5

In reference example 4-1-5, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=38:20:42, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 4-1-6

In reference example 4-1-6, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1.0 μm, P content 2 wt %. Au layer isformed as thickness 0.05 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=40:25:35, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-1-7

In reference example 4-1-7, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 0.03 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1.0 μm, P content 9 wt %. Au layer isformed as thickness 0.02 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=40:25:35, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-1-8

In reference example 4-1-8, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn: 97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 0.03 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Au layer isformed as thickness 0.05 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=40:25:35, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-1-9

In reference example 4-1-9, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.5 μm.

REFERENCE EXAMPLE 4-1-10

In reference example 4-1-10, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 2 wt %. Au layer is formedas thickness 0.02 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 4-1-11

In reference example 4-1-11, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 17 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 9 wt %. Au layer is formedas thickness 0.03 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 4-1-12

In reference example 4-1-12, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 17 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Au layer isformed as thickness 0.05 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 4-1-13

In reference example 4-1-13, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 0.03 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 2 wt %. Au layer is formedas thickness 0.008 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-1-14

In reference example 4-1-14, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 0.03 μm, P content 16 wt %. On the other hand, Pdlayer is formed as thickness 1 μm, P content 9 wt %. Au layer is formedas thickness 0.008 μm. Therefore, the composition of the Ni—Sn alloylayer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-1-15

In reference example 4-1-15, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 0.4 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 2 wt %. Au layer isformed as thickness 2.1 am. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 4-1-16

In reference example 4-1-16, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer. Ni layer isformed as thickness 12 μm, P content 17 wt %. On the other hand, Pdlayer is formed as thickness 1.5 μm, P content 9 wt %. Au layer isformed as thickness 2.1 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Cu:Ni=39:26:49, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 4-2-1

In reference examples 4-1-1 to 4-1-16, the Cu/Ag/Sn solder which doesnot include lead is used as the solder consisting of the solder layer.Whereas, in reference examples 4-2-1 to 4-2-16, an alloy of Sn:Pb=63:37(wt %) is used as a solder consisting of the solder layer. Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Pdlayer is formed as thickness 0.5 μm, P content 0 wt %. Au layer isformed as thickness 0.03 μm. Therefore, the composition of the Ni—Snalloy layer becomes Sn:Ni=67:33, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 4-2-2

In reference example 4-2-2, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 0.8 wt %. Au layer is formed as thickness 0.03 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-2-3

In reference example 4-2-3, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.0 μm, P content 9 wt %. Au layer is formed as thickness 0.04 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 4-2-4

In reference example 4-2-4, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness 5μm, P content 4 wt %. On the other hand, Pd layer is formed as thickness1.5 μm, P content 9 wt %. Au layer is formed as thickness 0.02 μm.Therefore, the composition of the Ni—Sn alloy layer becomes Sn:Ni=67:33,the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 4-2-5

In reference example 4-2-5, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Au layer is formed as thickness 0.03μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.8 μm.

REFERENCE EXAMPLE 4-2-6

In reference example 4-2-6, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.05μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-2-7

In reference example 4-2-7, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Au layer is formed as thickness 0.02μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-2-8

In reference example 4-2-8, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Au layer is formed as thickness 0.05μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-2-9

In reference example 4-2-9, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 0.5 μm, P content 0 wt %. Au layer is formed as thickness 0.03μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.5 μm.

REFERENCE EXAMPLE 4-2-10

In reference example 4-2-10, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.02μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 4-2-11

In reference example 4-2-11, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Au layer is formed as thickness 0.03μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.7 μm.

REFERENCE EXAMPLE 4-2-12

In reference example 4-2-12, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Au layer is formed as thickness 0.05μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.9 μm.

REFERENCE EXAMPLE 4-2-13

In reference example 4-2-13, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 2 wt %. Au layer is formed as thickness 0.008μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-2-14

In reference example 4-2-14, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness0.03 μm, P content 16 wt %. On the other hand, Pd layer is formed asthickness 1 μm, P content 9 wt %. Au layer is formed as thickness 0.008μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 0.9 μm.

REFERENCE EXAMPLE 4-2-15

In reference example 4-2-15, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 0.4 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 2 wt %. Au layer is formed as thickness 2.1μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.6 μm.

REFERENCE EXAMPLE 4-2-16

In reference example 4-2-16, an alloy of Sn:Pb=63:37 (wt %) is used as asolder consisting of the solder layer. Ni layer is formed as thickness12 μm, P content 17 wt %. On the other hand, Pd layer is formed asthickness 1.5 μm, P content 9 wt %. Au layer is formed as thickness 2.1μm. Therefore, the composition of the Ni—Sn alloy layer becomesSn:Ni=67:33, the thickness becomes 2.7 μm.

COMPARATIVE EXAMPLE

In comparative examples, as the conductive layer of the solder pad part,conventional nickel (Ni layer)-gold (Au layer) are formed.

Comparative Example 1-1-1

In Comparative example 1-1-1, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder bump Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Aulayer is formed as thickness 0.03 μm on the Ni layer, instead of Pdlayer. Therefore, the Ni—Sn alloy layer is not formed after the reflow.

Comparative Example 1-2-1

In comparative example 1-2-1, an alloy of Sn:Pb=63:37 (wt %) is used asa solder consisting of the solder bump. Ni layer is formed as thickness5 μm, P content 1.2 wt %. On the other hand, Au layer is formed asthickness 0.03 μm on the Ni layer, instead of Pd layer. Therefore, theNi—Sn alloy layer is not formed after the reflow.

Comparative Example 2-1-1

In Comparative example 2-1-1, an alloy of Cu:0.2 wt %, Ag: 1 wt %, Sn:97wt % is used as a solder consisting of the solder layer Ni layer isformed as thickness 5 μm, P content 1.2 wt %. On the other hand, Aulayer is formed as thickness 0.03 μm on the Ni layer, instead of Pdlayer. Therefore, the Ni—Sn alloy layer is not formed after the reflow.

Comparative Example 2-2-1

In comparative example 2-2-1, an alloy of Sn:Pb=63:37 (wt %) is used asa solder consisting of the solder layer. Ni layer is formed as thickness5 μm, P content 1.2 wt %. On the other hand, Au layer is formed asthickness 0.03 μm on the Ni layer, instead of Pd layer. Therefore, theNi—Sn alloy layer is not formed after the reflow.

(Evaluation Items)

For evaluation of this board, 10 specimens, each processed individually,were used. Parameters of the first to fourth embodiments, referenceexamples 1-4 and comparative examples are shown in FIGS. 31-47, and theevaluation results are shown in FIGS. 48-64.

1. Solder Peeling Test

After solder paste was applied, a solder paste peeling test was carriedout. Instances where a value in tensile strength of over 4.0 Kg/pin(solder bump or solder layer) was obtained are annotated with a

, instances where a value in tensile strength of 2.0-4.0 Kg/pin wasobtained, with a ◯, instances where a value of 1.0-2.0 Kg/pin wasobtained, with a Δ, and instances where a value of less than 1.0 Kg/pinwas obtained, with an X.

2. Reliability Test

First embodiment, third embodiment, first reference example, thirdreference example group: measurement of resistance after IC chip hasbeen mounted.

Second embodiment, second embodiment, fourth reference example, fourthreference example group: measurement of resistance after installation ona mother board

Under heat cycle conditions (135° C./3 minutes-−55° C./3 minutes as acycle), a reliability test was carried out every 500 cycles from 2500cycles to 50,000 cycles.

At this time, after being taken out of a reliability test machine andleft for two hours, a determination was made as to whether or notconductivity was found and resistance value were measured. Instanceswere conductivity was found, and a change of resistance conductivity wasfound, and a change of resistance was over 2% and less than 5%, areannotated with a ◯, instances where a change of resistance was over 5%are annotated with a Δ and instances where conductivity was lost areannotated with an X.

3. Peeling Test of a Chip/Mother Board after a Reliability Test

Pulling resistance was measured on a board, the installation of whichhad been completed and on which a reliability test had been completedover 5000 cycles under heat cycle conditions (135° C.-−55° C. as acycle). Instances where a value in tensile strength of 1.0-2.0 Kg/pin(solder bump or solder layer) was obtained are annotated with a ◯ andinstances where a value of less than 1.0 Kg/pin was obtained areannotated with an X. This evaluation was carried out in three locationsand results were evaluated in terms of their minimum values.

<Confirmation of Factors Test for the Palladium Film of the First AndSecond Embodiments>

Next the results will be described of a confirmation of factors test onthe palladium film.

A board of the first embodiment was manufactured under conditions A andB under the following conditions:

-   Condition A-1 (Δ) nickel thickness 0.05 μm, amount of the content of    P in the nickel 0.5 wt %-   Condition A-2 (◯) nickel thickness 0.05 μm, amount of content of P    in the nickel 6.0 wt %-   Condition A-3 (X) nickel thickness 0.05 μm, amount of the content of    P in the nickel 15.0 wt %-   Condition B-1 (Δ) nickel thickness 10.0 μm, amount of the content of    P in the nickel 0.5 wt %-   Condition B-2 (◯) nickel thickness 10.0 μm, amount of the content of    P in the nickel 6.0 wt %-   Condition B-3 (X) nickel thickness 10.0 μm, amount of the content of    P in the nickel 15.0 wt %    (Correlation with Thickness of Palladium)

After the thickness of the palladium was set to 0.008 μm, 0.01 μm, 0.03μm, 0.1 μm, 1.0 μm and 1.2 μm with the amount of the content of phosphorin the palladium film set to 5 wt %, a solder having Cu:0.5 wt %, Ag:3.5wt % and Sn:96 wt % was loaded, and a dummy semiconductor was mounted.

Thereafter, a PCT (pressure cooker test) was carried out (underconditions of 2 atm at 130° C.) for a period of 100 hours so as toexecute a pulling test in three locations, and an average value wascalculated. The results in each case are shown in the graph in FIG. 65.

(Correlation with the Amount of the Content of Phosphor in thePalladium)

After the amount of the content of phosphor in the palladium was set to0 wt %, 1 wt %, 2 wt %, 4 wt %, 6 wt %, 7 wt %, 8 wt % and 9 wt % withthe thickness of the palladium set to 0.1 μm, a solder having Cu: 0.5 wt%, Ag: 3.5 wt %, Sn: 96 wt % was loaded, and a dummy semiconductor wasmounted.

Thereafter, a PCT (pressure cooker test) was carried out (undercondition of 2 atm at 130° C.) for a period of 100 hours so as toexecute a pulling test in three locations, and an average value wascalculated. The results in each case are shown in the graph in FIG. 66.

<Confirmation of Factors Test for the Nickel Film of the First andSecond Embodiments>

Next, the results of the confirmation of factors test of the nickel filmwill be described.

Boards of the first embodiment were manufactured under conditions C andD as follows.

-   Condition C-1 thickness of palladium 0.01 μm, amount of the content    of P (phosphor) in the palladium 2 wt %-   Condition C-2 thickness of palladium 0.01 μm, amount of the content    of P (phosphor) in the palladium 5 wt %-   Condition C-3 thickness of palladium 0.01 μm, amount of the content    of P (phosphor) in the palladium 7 wt %-   Condition D-1 thickness of palladium 1.0 μm, amount of content of    phosphor in the palladium 2 wt %-   Condition D-2 thickness of palladium 1.0 μm, amount of content of    phosphor in the palladium 5 wt %-   Condition D-3 thickness of palladium 1.0 μm, amount of content of    phosphor in the palladium 7 wt %-   (Correlation with the Thickness of the Nickel)

After the thickness of the nickel was set at 0.03 μm, 0.05 μm, 0.1 μm,0.3 μm, 1.0 μm, 2.0 μm, 5 μm, 10 μm and 12 μm with the amount ofphosphor in the nickel film set to 6.0 wt %, a palladium film was formedunder the following condition.

(Correlation with the Amount of the Content of Phosphor in the Nickel)

With the thickness of nickel set to 0.1 μm, the amount of content ofphosphor in the nickel was set at 0 wt %, 0.5 wt %, 1 wt %, 3 wt %, 5 wt%, 8 wt %, 10 wt %, 15 wt %, and 17 wt %.

Then, a solder having Cu: 0.2 wt %, Ag: 1 wt %, Sn: 97 wt % was loadedand a dummy semiconductor was mounted. Thereafter, a PCT (pressurecooker test) was carried out (under condition of 2 atm at 130° C.) for aperiod of 100 hours so as to execute a pulling test in three locationsand an average value was calculated. As for the results in each case,the correlation between the thickness and the strength of the nickel isshown in the graph in FIG. 67, and the correlation between the nickeland the phosphor in the amount of the content is shown in the graph ofFIG. 68.

When, on the basis of the results of the experiments, simulation ofresistance to pulling was performed for thicknesses of the Ni—Sn alloylayer (in this case, Ni—Sn—Cu was used for evaluation), the relationshipshown in the graph of FIG. 69 was discovered.

<Confirmation of Factors Test of Palladium Film in the Third and fourthembodiments>

Next, the results of the confirmation of factors test of the palladiumfilm in the third and fourth embodiments will be described. Boards ofthe third embodiment were manufactured under the conditions A and B thathave already been described above.

(Correlation with the Thickness of the Palladium)

With the amount of the content of phosphor in the palladium film set to5 wt %, the thickness of palladium was set at 0.008 μm, 0.01 μm, 0.03μm, 0.1 μm, 1.0 μm and 1.2 μm. Thereafter, a solder having Cu: 0.5 wt %,Ag: 3.5 wt % and Sn: 96 wt % was loaded, and a dummy semiconductor wasmounted.

As can be evidenced from the graph of FIG. 65, the results of the PCT(pressure cooker test) were substantially the same as in the firstembodiment.

(Correlation with the Amount of the Content of Phosphor in thePalladium)

With the thickness of palladium set to 0.1 μm, the amount of the contentof phosphor in palladium was set at 0 wt %, 1 wt %, 2 wt %, 4 wt %, 6 wt%, 7 wt %, 8 wt % and 9 wt %. Thereafter, a solder having Cu: 0.5 wt %,Ag: 3.5 wt %, Sn: 96 wt % was loaded and a dummy semiconductor wasmounted.

As is apparent from FIG. 66, the results of the PCT (pressure cookertest) were substantially the same as in the first embodiment.

<Confirmation of Factors Test of the Nickel Film According to the Thirdand Fourth Embodiments>

The results of the confirmation of factors test of the nickel film inthe third and fourth embodiments of the present invention will now bedescribed. Boards of the third embodiment were manufactured underconditions C and D that have already been described above.

(Correlation with the Thickness of the Nickel)

With the amount of the content of phosphor in the nickel film set to 6.0wt %, the thickness of the nickel was set at 0.03 μm, 0.05 μm, 0.1 μm,0.3 μm, 1.0 μm, 2.0 μm, 5 μm, 10 μm and 12 μm. Thereafter, the palladiumfilm was formed under the following condition.

(Correlation with the Content of Phosphor in the Nickel)

With the thickness of the nickel set to 0.1 μm, the amount of thecontent of phosphor in the nickel was set at 0.5 wt %, 1 wt %, 3 wt %, 5wt %, 8 wt %, 10 wt %, 15 wt % and 17 wt %.

Then, a solder having Cu: 0.2 wt %, Ag: 1 wt %, Sn: 97 wt % was loaded,and a dummy semiconductor was mounted. As is apparent from FIGS. 67 and68, the results of the PCT (pressure cooker test) were substantially thesame as in the first embodiment that has already been described.

When, on the basis of the results of these experiments, simulation ofresistance to pulling was performed for thicknesses of the Ni—Sn alloylayer (in this case, evaluation was carried out with Ni—Sn—Cu), the samerelationship was discovered as in the first embodiment alreadydescribed, as is apparent from FIG. 69.

Trends apparent from the <confirmation of factors test of the palladiumfilm in the first-fourth embodiments> and the <confirmation of factorstest of the nickel film in the first-fourth embodiments> have beenconfirmed as identical to the case in where the external terminal wasdisposed as the solder layer. Further, substantial variations in thetrend were not apparent from the various types of solder tested (soldercomposition).

<Confirmation of Factors Test of the Corrosion Resistant Film of theThird and Fourth Embodiments>

Next, the results of the confirmation of factor test of the corrosionresistant film will be described. Boards of the third embodiment weremanufactured under the following conditions.

-   (Correlation with the Thickness of Gold)-   Thickness of nickel: 0.3 μm, amount of the content of phosphor in    the nickel: 5 wt %-   Thickness of palladium: 0.5 μm, amount of the content of phosphor in    the palladium: 5 wt %-   Thereafter, the thickness of the gold was set at 0.01 μm, 0.03 μm,    0.05 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1.0 μm, 2.0 μm, and 2.5 μm.    (Correlation with Other Corrosion Resistant Layers)

Corrosion resistant layers were formed with silver, platinum and tininstead of gold set at 0.03 μm.

After the corrosion resistant layers were formed, a solder having Cu: 2wt %, Ag: 1 wt % and Sn: 97 wt % was loaded, and a dummy semiconductorwas mounted.

Thereafter, a PCT (pressure cooker test) was carried out (underconditions of 2 atm at 130° C.) for a period of 100 hours so as toexecute a pulling test at three locations, and the results of acalculation of an average value at this time are shown in the graph ofFIG. 70.

1. A manufacturing method for a solder pad structure, comprising:providing a composite layer comprising an Ni layer and a Pd layer on afront surface of a conductor circuit exposed from an opening in a solderresist layer; providing a solder on the composite layer; and forming asolder bump by reflowing the solder and by forming a Ni alloy layer or aNi—Sn alloy layer on an interface between the Ni layer and the solderbump, wherein both the Ni layer and Pd layer include P, and the Ni layerincludes P in an amount of 0.5-5.0 wt %, and the amount of P in the Nilayer is smaller than an amount of P in the Pd layer.
 2. Themanufacturing method of a printed wiring board according to claim 1,wherein the Pd layer is provided in a thickness of 0.01-1.0 μm.
 3. Themanufacturing method of a printed wiring board according to claim 1,wherein the Pd layer is provided so as to contain P of 2-7 wt %.
 4. Themanufacturing method of a multilayered printed wiring board according toclaim 1, wherein a thickness of the Ni layer is 0.05-10 μm.
 5. Themanufacturing method of a printed wiring board according to claim,wherein the Ni layer contains P of 0.5-15 wt %.
 6. The manufacturingmethod of a printed wiring board according to claim 1, wherein the Nilayer contains P in a larger amount of content than an amount of P inthe Pd layer.
 7. The manufacturing method of a printed wiring boardaccording to claim 1, wherein the solder comprises Cu—Sn—Ag and theNi—Sn alloy layer comprises Cu—Ni—Sn.
 8. A manufacturing method of asolder pad structure, comprising: providing a composite layer comprisinga Ni layer, a Pd layer and a corrosion resistant layer on a frontsurface of a conductor circuit exposed from an opening in a solderresist layer; providing a solder on the composite layer; and forming asolder bump by reflowing the solder and by forming a Ni alloy layer or aNi—Sn alloy layer on an interface between the Ni layer and the solderbump, wherein both the Ni layer and Pd layer include P, and the Ni layerincludes P in an amount of 0.5-5.0 wt %, and the amount of P in the Nilayer is smaller than an amount of P in the Pd layer.
 9. Themanufacturing method of a printed wiring board according to claim 8,wherein the solder comprises Cu—Sn—Ag and the alloy layer comprisesCu—Ni—Sn.
 10. The manufacturing method of a printed wiring boardaccording to claim 8, wherein a thickness of the Ni alloy layer is1.0-2.5 μm.